Emu, a clumsy pediatrics intern takes young Sota, who is suffering a mysterious illness, to the announcement event of the latest "Mighty Action X", Sota's favorite game. Emu became a medical doctor in order to save someone's life because his life had been saved once through surgery.

However, a mysterious virus emerges from Sota's body and the event turns into chaos. Emu hears from Asuna, an employee of the Ministry of Health, that transforming into a Kamen Rider can save the patient. Emu takes on this "operation" and inserts the Mighty Action X Gashat into the Gamer Driver, transforming into Kamen Rider Ex-Aid!

Becoming Kamen Rider Ex-Aid, Emu now must serve as both a pediatrician and a member of CR. A gifted surgeon named Hiiro Kagami comes back from the United States and is not only the son of the director, he’s also Kamen Rider Brave. This results in a clash of ethics when it comes to dealing with patients.

Emu follows a patient who’s fled in fear of a doctor and encounters Taiga, who transforms into Kamen Rider Snipe. Once Emu learns of the past connection Taiga had to CR, he visits the dark hospital Taiga resides in to rescue the patient.

Emu cannot transform into a Kamen Rider since Taiga stole his Gashat. Medical Examiner Kiriya Kujo appears before a crestfallen Emu. He brings a Bugster-infected patient and offers to steal back Emu's Gashat in exchange of helping Kujo out with his prodigious gaming abilities.

When the thief of the 4 new Rider Gashats is infected with the Bugster virus, Emu and Hiiro clash about saving his life or not, and the identity of the mysterious Kamen Rider that is attacking the others is finally revealed.

The girlfriend of the student that the Bugsters were after has contracted the Game Disease. Hiiro transforms into Brave and succeeds in separating the Bugster from the girl.

A hospitalized patient showing two symptoms of the Game Disease has appeared. Emu and Hiiro transform and succeed in separating the two Bugsters from the patient. But Genm appears again to interfere, letting the Bugsters escape.

Taiga manages to capture the Bugster which escaped in the last episode and obtains the Jet Combat Gashat, holding the Bugster, and thus the patient, hostage in exchange for the other Riders' Gashats. When they arrive to challenge him, he decides only he is needed to fight the Bugster, and tries to destroy Ex-Aid and Brave.

Graphite infects the Deputy Director-General of the Ministry of Health with the Bugster Virus, while the doctors at the CR fall out over the most important course of action: Save the Patient or defeat Graphite?

Unable to control the powers of the new "Drago Knight Hunter Z" Gashat only by himself, Emu discovers that to do so he must convince the other Kamen Riders into join forces with him. Once he tricks them into doing so, the time comes for their showdown with Graphite.

Emu gives Kiriya another chance to earn his trust. Kiriya then takes the chance to finally reveal Kuroto's intentions and expose him as the Black Kamen Rider that is working with the Bugsters.

With Christmas around the corner, Emu runs against time to defeat the Salty Bugster again and save another patient, while Kiriya's investigation leads him closer to the truth, but his life is in danger when he faces Kuroto's new power.

With the Bugster infection spreading rapidly, the authorities can't hide the disease from the public anymore. After Kiriya's death, Kuroto starts targeting the other Kamen Riders for their Gashats, but Parad approaches Emu, offering him a blank double Gashat which will allows him to attain a new level of power…

Ex-Aid, now as two, get into an argument about defeating Genm or the Aranbura Bugster. They both seem to be Emu, but Genm and the Bugster take this opportunity to escape. Emu reverts to his human form and falls unconscious.

Wanting to save Dr. Shirakawa, Emu asks Hiiro to perform a surgery on his cancer. He has his Gashat back and faces the Aranbura Bugster to also cure Shirakawa's game illness. Will the surgery succeed? What will happen to Ex-Aid?!

Taiga tries to find out more about Emu's infection, and starts to discover the secret that might be why Kiriya was killed. Meanwhile, using data collected from fights with Mighty Brothers XX, Parad makes his move and reveals his new form: Kamen Rider Para-DX Level 50.

Emu thinks Taiga and Hiiro attacked him since he is the source of stress for Nico, who is suffering the Game Disease. He does not realize the true intention of the other two riders is to eliminate the Bugster virus residing in Emu himself, who is unknowingly infected with the disease as well.

Brave attacks Ex-Aid again but Revol Bugster and some grunts appear to…defend Emu! He is further convinced he is the source of Nico’s stress. Genm Level X appears and attacks both riders. He succeeds in stealing all of Hiiro’s Gashats and seems intent to do the same with Emu’s.

A lovable hamburger Bugster named Burgermon appears. Emu transforms into Ex-Aid, but attacking it causes the game disease patient to suffer from stress. What is this?

The CR accommodates an employee of the Genm Corporation’s development department. A game called Ju Ju Burger is under development with a game virus infection, and Burgermon seems to be separated from the game. Burgermon acts like an adorable child; he doesn’t seem so bad. As expected, Emu will have to deal with what’s in control of his head.

"Hiiro, are you hiding something from me?" Emu calls out Hiiro on the roof of the hospital. In the last battle, Genm tells Emu that he saved the Bugster because his body told him to do so. Emu also suffers from serious headaches after every transformation since creating the Mighty Brothers XX Rider Gashat. And most of all, Emu is incompatible with the surgery and yet he can still transform into a Kamen Rider. Everything is starting to come together, so what will Hiiro's response be? Meanwhile, Kuroto Dan returns to Genm Corp., and using the Gashacon Bugvisor, he begins to spread the Bugster Virus...

Emu finally learns of the horrifying truth that he has the game illness. The Bugster virus in him acts up and he collapses to the ground, though for some reason no Bugster has appeared...

Emu later wakes up in CR with his personality completely changed to that of "Genius Gamer M". When a new Level 30 Bugster emerges, Emu transforms into Ex-Aid with delight, and fights as if he were playing a game while no longer concerning himself with the patient. Just what has happened to Emu?

Taiga and Nico meet a high school student named Daisuke who is infected with the Bugster Virus and calls both Emu and Hiiro for their help. Parado suddenly appears and Hiiro faces him in his new form while Emu is hesitant on joining the fight.

Emu and Hiiro learned from Poppy that Kuroto was the one who had suggested Emu to CR. Meanwhile, a police detective is investigating the Zero Day case, causing him to interrogate Kuroto's father, Masamune. During the investigation, he gets infected by the Game Illness. In order to save him, Emu confronts Masamune.

Kuroto falls victim to the Bugster virus and is aprehended by the authorities. Despite everything Kuroto did to him and his friends, Emu is determined to treat him, but the others are wary, wondering if saving Kuroto's life is worth the effort, or even if he will be grateful for it. On the other sides, Hiiro finds some very useful information from Kiriya Kujo's belongings while Emu receives an emergency call that a Bugster is rampaging on a certain location.

Recovered from his infection, Kuroto resumes his plans to complete "Kamen Rider Chronicle" and the members of CR seem to have no way to stop him, until Taiga gives Emu a new Gashat that brings forth a power never seen before.

The fierce battle between Ex-Aid and Genm has now come to an end. Meanwhile, a woman who was injured, Sora, is brought to Emu and Hiiro. Sora's band members argue, when suddenly all 3 of them are taken over by Bugsters! And on top of that, when Emu tries facing them alone, a young man appears yelling, "Yossha Lucky!"

Recently, Emu has been feeling a little worried. He is very quiet and hasn't talked much since Poppy Pipopapo suddenly disappeared. Just then, Hiiro is shocked by the sheer number of emergency calls coming to CR, all reports of the game illness! As the only CR doctors, Emu and Hiiro rush to the indicated locations, but what they find there is an unbelievable sight...

Kamen Rider Chronicle has already begun! Para-DX has joined the game and defeated the first round of the general players, giving them a Game Over as Emu watched them disappear before him. Kamen Rider Chronicle is being sold at an extremely fast rate, which catches the attention of the Ministry of Health. To avoid any form of confusion, Kyotaro Hinata orders a temporary halt on the actions of the doctors in CR. However, a game disease patient escapes from CR in an attempt to cure his own game disease, which leads Emu to chase after him. Then suddenly, Poppy Pipopapo appears before them with a new Driver and a Rider Gashat of her own…

Thanks to the public announcement by the Ministry of Health, the number of Kamen Rider Chronicle players seems to have decreased significantly, which would subsequently reduce the amount of game disease patients. However, unbelievable information about Kamen Rider Chronicle is released by Ren Amagasaki, the new CEO of Genm Corp. There is a hidden component inside Kamen Rider Chronicle, one that is said to dramatically increase player participation! However, Taiga, who was suspicious of the love and go CEO's actions, goes into Genm Corp. to confront him himself...

Emu managed to notice Poppy smiling after the Rider's battle against Lovelica. With her sudden change of heart, Emu believes that she was suddenly swept up in all the commotion. Although he was attacked by Kamen Rider Poppy, Emu does not believe she is a bad Bugster. When Kamen Rider Chronicle starts up once again, Poppy Pipopapo is summoned. When Emu confronts her, he shouts "You aren't like this!" to her, just as she appears to deliver the final attack at the Riders who violated the game...

It was Emu who managed to return Poppy Pipopapo back to normal thanks to the bond they share, but it was not a time for relief. Suddenly Parado begins to manipulate Emu! "Let's do this, the most exciting of all games!" Emu managed to remove the Gashat Gear Dual that transforms Parado into Kamen Rider Para-DX and uses it himself! Just what on Earth is going on?! Finally, the points connecting Emu and Parado are beginning to reveal themselves...

Ex-Aid, Brave, and Snipe have all been defeated at the hands of Kamen Rider Para-DX Level 99! Also, Parado begins to manipulate Emu's body as his own in order to retain the infection. Much to the other Rider's surprise, Poppy brings out another Proto Mighty Action X Gashat and a Gamer Driver! Poppy had found them thanks to her revived memories of a young Kuroto. What is the meaning behind this Gashat? Poppy manages to use the power of Level 0, in the hopes of bringing Emu back to normal...

No one can hide the fact that they are upset about Kuroto's revival. How was he able to return? What is Kuroto's true intention by making this Continue a reality? Meanwhile, Emu cannot forgive what Kuroto did to all those patient's lives. He realizes that in order to eliminate Kamen Rider Chronicle, his cooperation is required, but Emu is getting tired of his attitude...

Ex-Aid and crews have gained the right to challenge the advanced Bugsters in order to clear Kamen Rider Chronicle. The three advanced Bugsters are Parado, Graphite, and Lovelica. The time of the final battle against the four Kamen Riders is at hand! At last, the curtain rises on the scene of the last battle! However, a disturbing darkness suddenly begins to appear...

Masamune Dan as Kamen Rider Cronus instantly killed Lovelica with his Pause attack, which freezes the game in time! The Bugsters and CR are greatly upset by Cronus' sudden appearance, Parado frozen in fear. Furthermore, it seems that the Proto Gashats being monitored by the Ministry of Health have been stolen by him! Now the doctors have been deprived of the data of the past Ride-Players. Emu goes to visit Masamune Dan, once again the CEO of Genm Corp. ...

The fact that Hiiro has betrayed Emu weighs heavy on the members of CR. If Hiiro is working with Masamune, then there can only be one reason for it. With everyone on the ropes about the situation, suddenly both Parado and Graphite show up in CR! To counter against Cronus, they ask Kuroto about Kamen Rider Chronicle's final boss, Gamedeus, the only being who can defeat Cronus. Just then, Brave confronts Ex-Aid as he is responding to an emergency call...

Apparently Hiiro wasn't the only accomplice that Masamune had in the palm of his hand! Cronus suddenly summons Kamen Rider Lazer Turbo Level 0 into the fight! In order to further expand the presence of Kamen Rider Chronicle around the world, Lazer Turbo stands before the Doctor Riders in an attempt to keep them from ending the game! Much to the shock of everyone, Kamen Rider Lazer Turbo finally reveals his identity...

Genm Corp. announces a new addition to Kamen Rider Chronicle, the "Cronus Capture Quest", and despite knowing what dangers lie ahead, countless new players join the game! Meanwhile, Emu is still reminded of the message Kiriya said to him before Masamune took him away. Kuroto completes an invincible golden Gashat holding an unbelievable amount of hidden power! Ex-Aid and the others rush to stop the "Cronus Capture Quest" as Brave and Lazer Turbo stand in their way once again...

Ex-Aid finally went Muteki and was able to beat Cronus! Masamune, who does not like the fact that Ex-Aid was able to attain a power that exceeded his control, angrily forces Hiiro to work for him as he claims Saki as a hostage! Brave forcibly renews his resolution, and this time he is able to transform into Legacy Gamer Level 100! Emu is more confused than ever, while Taiga is the only one who truly understands just how painful Hiiro's decision truly is…

Graphite mercilessly attacked the body of Taiga which forced him out of his transformation! The injured Taiga has been rushed to the hospital immediately, but there is a high possibility that his heart has been damaged. Moreover, it seems that it would take an expert-level of surgical expertise in order to save his life. After returning to Masamune, Hiiro's father and Asuna make an urgent phone call. The director asks Hiiro to perform Taiga's surgical operation. Just what decision will Hiiro come to in the end?

In order to deprive Ex-Aid of his transformation abilities, Cronus decides to target Parado directly. Para-DX without Emu is still not perfect, so he is beaten easily. Even so, Ex-Aid cannot stop chasing Cronus. However, Cronus was planning an underhanded scheme. Nico's game disease, which just started to show symptoms, belongs to that of Gamedeus, the Last Boss of Kamen Rider Chronicle! In order to defeat Gamedeus, Ex-Aid has to defeat both Graphite and Parado! Just then…Parado's hands begin to shake violently…

Parado has been defeated, and Emu has lost the ability to transform into Ex-Aid! Following Parado's annihilation, the other Riders team up in order to defeat Cronus. Brave, Snipe, Genm, and Lazer Turbo, all alternate the Hyper Muteki Gashat in order to counteract Cronus' Pause. Meanwhile, Emu was deep in thought. The fear of death that he felt at the moment of his extinction, even if he was a Bugster, he shared the same feeling as he did in that moment. Just then, Emu takes out the Mighty Brothers XX Gashat…

Kamen Rider Chronicle has been reset thanks to Masamune's special ability! Thanks to his Bugster infection, his hidden power has awakened, and the game is reset to the moment before Emu received the Hyper Muteki Gashat! Finally, with Parado having already been defeated, Graphite is the only game character left in order to clear Kamen Rider Chronicle! Brave and Snipe both challenge Graphite with a burning fighting spirit. Meanwhile, Emu believes that Graphite infected with Gamedeus' virus may be the only one strong enough to defeat Cronus. However, Graphite refuses to cooperate with the Riders…

The Last Boss of Kamen Rider Chronicle, Gamedeus, is finally born! If you defeat Gamedeus, then the game will end! However, at the moment of Gamedeus' revival, massive amounts of the Bugster Virus spread throughout the city! The number of infected patients are increasing, as well as the number of people being rushed to the hospital. While the doctors attend to the patients, Ex-Aid and Para-DX team up to fight Gamedeus! But their strength is far too weak against Gamedeus, as he sends them flying easily. At the same time, two people were confronting each other. Kiriya and Kuroto, both transformed, clash fists to see who's fate will be decided in the end…

Suddenly, the Gamedeus virus begins spreading through the streets! Masamune becomes Gamedeus Cronus and appears before the other Riders, as he summons Nico into the World of Kamen Rider Chronicle! Nico is the one who is qualified to challenge the Last Boss of Kamen Rider Chronicle as a Ride-Player, but it seems clear that Masamune is going to try to Game Over the player who is closest to beating the game in order to reset it. In an attempt to save her but unwilling to let the others follow, Taiga uses the Chronicle Gashats seized from patients and goes to find her. However, the other Riders cannot enter the World of Kamen Rider Chronicle! Just what will happen to Nico's fate?

Gamedeus Cronus has grown massive and become the strongest Last Boss! The Gamedeus Virus expanded and the pandemic has gotten worse. The Gamedeus Virus can now be transferred from person to person, turning the infected into Bugster Virus foot soldiers! Two Bugsters witnessing this symptom, Parado and Poppy Pipopapo, decide to take action. "There is something that only us Bugsters can do…" Poppy says as she rushes to Ex-Aid…

Though Gamedeus was finally destroyed at the cost of Poppy Pipopapo and Parado when they extracted the Bugster from his body, Masamune Dan survived and takes advantage of Emu no longer being able to use Hyper Muteki. The Kamen Riders are at a huge disadvantage, while Cronus doesn't hold back, and initiates Pause. All of the Kamen Riders' movements are frozen in time, and he prepares to kill them, starting with Emu…

桐生战兔在东都先进物质物理研究所开始了他的新工作，研究神秘的潘多拉魔盒。在回应潜在的粉碎目击事件时，战兔遇到了一个被通缉的逃犯......

东都的假面骑士现在是一名逃犯，因为他拯救了一个被定罪的杀人犯 - 万丈龙我。桐生在他和龙我所经历的神秘实验中看到相似之处。

对龙我被绑架的调查导致一个名叫锅岛的男人。但为了得到他需要的答案，龙我必须越过边境去西都......

过去的谜团随着战兔调查潘多拉魔盒灾难而继续堆积。在西都，龙我和纱羽继续寻找锅岛的家人。

战兔质问业主与浮士德的关系。纱羽在战兔难以捉摸的过去中找到了线索。

龙我找到了浮士德隐藏基地的入口。为了了解更多，战兔了解到葛城已故对“星云气体”的研究。

战兔和龙我需要更多地了解巧和他的研究。将目光投向北都，他们首先要穿过天空之墙......

现在藏在北都，战兔和龙我试图从母亲那里了解更多关于葛城巧的信息，并找到他隐藏的项目数据。

关于葛城巧研究性质的争论导致了战兔和龙我之间的另一场争吵。在支持者的压力下，浮士德策划了一个窃取潘多拉魔盒的计划。

随着日本三位首相的会面，血潜领导了对东都先进物质物理研究所的攻击。

现在，他的大部分满瓶都在夜霸手中，钱藤展示了他的王牌——龙贺使用构建驱动程序的一种方式。

纱羽揭示了浮士德、难波重工和东都政府之间的联系。战兔和龙我计划找回潘多拉魔盒。

锅岛的突然召唤为战兔夺回潘多拉魔盒的计划奠定了基础，也有机会捕获难以捉摸的血潜......

血潜的身份暴露，战兔争分夺秒地完成对他的反制措施。

在潘多拉魔盒安全掌握后，战兔和龙我开始追捕浮士德，着手向公众揭示东都政府与浮士德之间的联系。

幻德揭示了战兔失踪记忆背后的真相，现实可能会撕裂他和龙我的友谊。

北都入侵东都，想夺取潘多拉魔盒。随着平民伤亡人数的增加，幻德政府煽动假面骑士作为他们的军事武器。

骑士大战中的新竞争者出现在战兔和龙我面前，不知何故，他拥有自己的挤压驱动器。北都自己的骑士Grease来了。

东都与北都骑士之间的另一场冲突以龙我从挤压驱动器的影响中挣扎而告终。北都乌鸦被血潜赋予了强化能力，但这是有代价的......

惣一给了战兔一个手段，阻止龙我对禁忌物品——危险扳机日益增长的愤怒。幻德策划了对北都入侵者的反击。

为了对抗龙我作为Cross-Z冲锋的横冲直撞，战兔被迫使用危险扳机。使用此禁忌物品的代价是什么？

东都和北都的政府已经下令进行一场赢家通吃的战斗，以决定谁保留潘多拉魔盒。这是Build与Grease来决定骑士战争的胜利者！

西都向和美空发出最后通牒——作为假面骑士为他们而战，或者目睹他家人的死亡。一个神秘的新对手前往东都与战兔和龙我对峙。

假面骑士Rouge暴露了自己,美空倒在基地内。

美空使假面骑士Rouge飞过天空墙;惣一向战兔透露，东户政府有间谍。

西都挑战东都进行三局两胜的战斗，以决定谁保留潘多拉魔盒;战兔努力寻找对抗黑色危险狂暴状态的方法。

龙我被骗输掉了比赛;Build和Rogue对峙，因为纱羽带着从战兔偷来的原理图来了。

假面骑士Rouge收到Build的兔子形态数据，迫使战兔释放坦克坦克形态;佐和的背景故事在和美空营救平民时被揭示;难波决定不公平，控制了濑户并宣战。

尽管他们做出了承诺，但西都继续对东都的攻击。当血潜完成潘多拉魔盒的面板时，这一切都变得更糟，天空墙开始移动......

面对自称为火星王妃：贝尔娜希的发生变异的美空，Stalk使用了从火星得到的力量对美空进行攻击；贝尔娜希所言的“万丈是最后的希望”，这句话对万丈是有什么含义呢？为了了解万丈的来世，战兔向纱羽请求收集万丈的身世资料，可是纱羽知道的却是令人震惊的真相……

纱羽根据战兔的请求寻找了万丈的过去，但纱羽所言“万丈有可能不是人类”这句话，这对万丈的冤罪有什么关联呢？为了调查Stalk的目的，幻德向万丈发出了挑战！面对Stalk使用潘多拉魔盒的力量而陷入苦战的战兔，为了拯救战兔，万丈的力量宛如火山喷发般地觉醒……

强化为Cross-Magma的万丈在战胜Stalk，成功夺回了潘多拉魔盒，但目睹万丈能使用潘多拉魔盒的力量和Stalk所言的“容器”跟“究极的驱动器”的战兔，感觉离万丈的冤案的真相越来越近了，同时纱羽通过特殊手段从难波综合研究所拿到了和万丈相关的检查治疗，发现担任负责人竟是失忆前的战兔：恶魔科学家·葛城巧的父亲，而万丈得知自己拥有地球外生命体·异星人的遗传因子而处于混乱之时，Stalk出现在万丈面前……

被Rogue抓去的冰室泰山关进了难波重工的监狱所，战兔为了对抗拥有火星之力的Stalk，用Build驱动器的设计图进行修改并得到改良，开发出了能将潘多拉魔盒的力量发挥到极限的新型驱动器，可是他们却不知道自己已经为敌人打开了禁忌之门，得到了关键的“究极驱动器”的Stalk变身成究极的全知全能战士：假面骑士Evol，以压倒性的实力对挑战自己的Rogue施展了制裁之锤……

为了保护自己儿子而死去的冰室泰山，Evolt将下一个目标转向了战兔，受到Evolt的攻击而中了地球没有存在的病毒，开始面临死亡边境的战兔，而万丈因为熔岩的力量而不断受到伤害，但他为了拯救战兔，他开始最后的变身……到底万丈和战兔的命运就此为止了吗？

被Evolt夺去身体的万丈，所有的能量瓶都在Evolt手上，世界已经开始要步入火星的命运，战兔为了阻止Evolt的阴谋，为了救回被Evolt夺去的万丈，他独人前去挑战Evolt，到底战兔能战胜Evolt吗？这个世界真的会面临毁灭的命运吗……

潘多拉之盒被打开，潘多拉之塔已经完全构成，现在就差Evolt将自己进入完全体状态，为了阻止Evolt进入完全体，贝尔娜希将潘多拉之盒的核心交给了战兔，但是如何能运用这个力量，战兔就在要陷入瓶颈期时，他想出了一种办法……

万丈被解放，但相应战兔却被Evolt附身，被战兔的将计就计而摆一道的Evolt声称要毁掉他所珍惜的一切，为了拯救被Evolt附身的战兔，万丈却发现自己无法变身，只能以肉身之躯迎战Evolt，失去变身能力的万丈在为了拯救指引自己走向正确的道路的搭档，他的信念使他持有的由Evolt从万丈身上孕生出来的进化龙瓶突然发生了变化……

战兔恢复了葛城巧的记忆，但相应的却失去了作为桐生战兔的记忆，甚至对于拥有Evolt遗传因子的龙我为何和自己行动感到不解。同时Evolt重新附上石动惣一身体，并背叛难波而掌管了西都，开始进行最终阶段。Build、Cross-Z、Grease、Rogue以及Remocon Bro′s在合力对付Evol时，一名拥有Evol Driver的新骑士乱入了战斗……

获得由Evolt赠送Evol驱动器，变身成假面骑士Mad Rogue的内海，以压倒性的实力战胜Rogue和Grease，一直渴望打倒Evolt和万丈的葛城开始沉迷开发究极强化道具，面对感觉变得如此陌生的他，美空仍然希望他还有以前的记忆……

重新恢复原来的记忆，并究极强化为天才Build的战兔，此时Evolt开始进一步的计划，声称自己要创造出一个新世界，而东都在遭到第二波攻击，就在战兔前去迎击时，一个意外性的人物作为第二波的带领者出场……

万丈和纱羽从曾经帮助自己偷渡到西都的木根礼香得知战兔的父亲在前几天坐过他们的船，深知葛城忍还幸存着，同时战兔通过天才之力将多治见体内的星云气体中和，让她避免了因过度注入气体而消灭的命运，但Evolt再次出现，战兔让一海带着多治见离开；开发失落能量瓶和还幸存在世还有Build的骑士系统的关键都在于葛城忍身上……

深知自己父亲开发出来的失落能量瓶是为了正确的道路使用，战兔开始将自己父亲的所在地锁定在Evolt身上而进行搜寻。但是深知自己父亲已经被潘多拉之盒的光芒照耀而变得好战性格以及十年内一直杳无音信的葛城巧和战兔的意见产生分歧。但就在这个时候，另一个假面骑士Build以兔坦模式出现在战兔面前……

战兔的父亲：葛城忍以Build的姿态出现在他们面前，面对一直相信自己的父亲，导致一海和幻德开始进行单独行动。就在战兔陷入低迷期时，美空收到了神秘的信息，出去后没有回来的美空，战兔在出去寻找时接到了美空的联络，听到对方的诉苦声而赶来时，他所面对的是被注入星云气体而变成Lost Smash的美空……

为了阻止Evolt的计划而潜入北都的一海和幻德，不料却被他们发现而遭到拘捕。战兔为了应付Evolt和自己的父亲，开发了拥有冻结能力的和终焉熔岩拳套的同款武装。但得知他们的情况而前往北都，首次的四名骑士合力战斗。到底他们能否战胜Evolt呢？

战兔他们终于打倒了Evolt，但这是葛城忍的计划，他将剩余的三瓶遗失能量瓶注入在Evolt身上，借此Evolt被打倒的契机，让这三瓶遗失能量瓶成功炼成，到底葛城忍所谓的超越物理法则的存在是什么呢？而这时，一个佩戴Evol驱动器的神秘怪人开始行动起来了……

战兔通过忍的提示而让万丈将危险扳机放入潘多拉魔盒，衍生出了白色遗失能量瓶嵌板。同时战兔上次开发的暴雪拳套其实是为了一海而开发出来的。只是因为事先没有说而导致一海注入星云气体的关系，一旦用于变身就会超越极限而消灭。赌上遗失能量瓶，Build、Cross-Z、Grease和Rogue与Evolto展开了最后的战斗……

一海在和由Evolto的遗传因子制作出来的拟态三羽鸦战斗时，他违背了战兔的约定，使用了忍遗留的Build驱动器变身成Grease Blizzard。另一方面，Evolto通过遗传因子拟态出了鹫尾兄弟，和内海一同对付幻德。只剩下战兔和万丈他们的情况下，终于赶到了塔顶……

现在幻德走了，是时候与Evolt进行最后的对抗了。

龙我带着Evolt飞走了。战兔决定去把他带回来，因为两个世界即将融合。

Sougo Tokiwa seems like an ordinary high school student, but one thing he has different is that he has dreams of becoming a king! One day, a mysterious young man appeared before him with a prophecy. "Congratulations! Today is a special day for you..." As Sougo is told these words, a giant red robot suddenly appears before him! This robot was a time machine, and Sougo was thrust across various timelines! In the year 2000, the battle of the Heisei Rider's fate, and Sougo's fate in his own birth year, is about to begin...!

The man who hails from the future, Geiz, attacks Sougo! Tsukuyomi, a girl who also hails from the future, came to help out Sougo, but Sougo has absolutely no idea what's going on! A mysterious prophet named Woz is also starting to appear frequently before Sougo. The creature, Another Build also attacks. What could be the key to defeating this "Kamen Rider Build"? Sougo makes his way towards the Nascita Cafe to meet with Kiryu Sento...

A strange collaboration between Geiz and Tsukuyomi happens with Sougo in the year of Build, 2017. They both decide to go to Sougo's school to keep a closer eye on him. While there, they discover a growing popularity of a "game that no one can clear" with the other students. Rumors surrounding the Genius Gamer M start to surface as well, as they decide to chase the mystery by finding him. And Sougo and the others end up meeting...? Suddenly, a new Time Jacker, Ora appears!

Ora has given a father the power of Another Ex-Aid as part of a bargain for his son's life. Geiz and Sougo travel back to 2016 to help him.

Tsukuyomi and Geiz learn that 18-year-old Libras have been going missing from Amanogawa High for years and want to check it out, thinking that it's probably an Another Rider plot; Schwartz makes his presence known to Uhr and Ora, forcibly creating a new Another Rider.

Takumi joins Sougo in protecting Karin from Another Fourze; Tsukuyomi and Geiz learn that Karin is actually much older than she looks.

Sougo learns of a magic show and wants to check it out. After seeing the magician in action, Geiz believes that he might have been given the powers of Kamen Rider Wizard and wants to fight him.

Geiz tracks down Kousuke in order to get his hands on the Wizard Ride Watch.

Uhr gives Kuroto Dan the powers of Kamen Rider OOO, which leads to Kuroto declaring himself king in 2018. Sougo finds common ground with this new Kuroto and wants to learn from him.

Sougo asks Kuroto just what type of king that he wants to be; Tsukuyomi learns to listen to all points of view.

Sougo and Tsukuyomi search for Geiz when Sougo notices the news that Team Baron dancers have been disappearing, but Tsukuyomi gets fed up with Sougo constantly returning just after leaving and having an inconsistent memory.

Sougo is revealed to have traveled back in time to save Geiz, and so there are two of him in the present, but Woz isn't very keen on this plan.

Takeru Tenkuuji and company have been hired by a woman to investigate Another Ghost after her brother mysteriously disappeared; a confrontation occurs with what appears to be Kamen Rider Agito.

With Sougo's soul separated from his body, he guides Takuru back to the year 2015 where Geiz has his Ghost watch taken from him in exchange for a Decade one.

Oma Zi-O sends a fleet of Dai Mazine to 2018 and a loyal follower to take out Geiz and Tsukuyomi; Tsukasa sends Sougo to meet his future self.

Sougo returns from the future and destroys his belt, ensuring that he will not become Oma Zi-O, but he is later attacked with no one to turn to for help.

Sougo has a dream that he is in the year 2022 and meets a man who goes by Kamen Rider Shinobi. Later, he encounters an Another Rider with the same attacks and a second Woz appears.

Sougo and crew are confused over the appearance of "White Woz"; Geiz and Tsukuyomi try time traveling to get the Kamen Rider Shinobi watch but are forbidden to land.

Sougo and Geiz head into battle with an Another Rider when the original Rider also arrives on the scene. How are both Kamen Rider Quiz and Another Quiz active at once?

Sougo works with Mondo to get answers from his dad and Geiz works with "White" Woz to stop Another Quiz.

Heure breaks a mirror and gives an Another Rider watch to a man inside; Sougo and Geiz have trouble defeating an enemy who keeps retreating even though he has nowhere to run.

Sougo battles with his self on the other side of the mirror; Geiz tries defeating Another Ryuga when things go horribly wrong.

Sougo falls asleep while studying and travels 100 years into the future to a world where humans and machines are at war; Tsukuyomi joins forces with White Woz.

Sougo dreams of Kikai going evil while Ora asks White Woz for help with Heure; Geiz asks Tsukuyomi if she really wants to align herself with White Woz.

A man with a connection to Sougo's past is taking the leftover energy from previous Another Riders.

Tsukuyomi travels back in time to investigate Hiryuu Kakogawa; White Woz tells Geiz that his watch won't activate until he's committed to killing Sougo.

After getting beat by Geiz, Black Woz goes to Ora and Heure for help; Schwartz recalls the first time he met Tsukuyomi.

Tsukuyomi learns about Sougo's past; Sougo and Geiz prepare for their showdown.

Kamen Rider DiEnd runs off with Sougo and Geiz's watches when Tsukuyomi gets word of Another Blade; Sougo forces Woz and Geiz to work together.

White Woz has Blade and Chalice fight to bring on the end of the world; Black Woz and Geiz settle their differences.

Sougo and crew watch a news report of the G3 unit getting attacked by Another Agito. When they arrive during another attack, Sougo learns that Another Agito is able to multiply and one freezes in front of Tsukuyomi.

The Timejacker steal the real Agito's power; Woz questions Schwartz about Tsukuyomi's newfound abilities.

It's Sougo's birthday and Woz wants to make it special; Sougo's former classmate who wanted to become an oni is turned into Another Hibiki.

Kyousuke has been outed as not being Hibiki; Sougo has Todoroki take Woz as his pupil for the day.

Sougo recalls his first love from elementary school; Ora recruits a woman falsely accused of murder to become Another Kiva; a new Kamen Rider falls from the sky.

Schwartz calls a temporary truce with the Kamen Riders to stop Ginga; Sougo tries to get Yuuko to stop her revenge.

Sougo and the others watch a news reporter turn into a monster; Tsukuyomi remembers a piece of her childhood; a meteor is heading for Earth.

The Hell Brothers steal the Fourze and Ginga watches so that Sougo and Woz cannot stop the asteroid; Tsukasa takes Tsukuyomi to visit her childhood home.

The DenLiner breaks down and the Imagin go to Junichirou to fix it; Yuuto Sakurai and Deneb emerge to stop Sougo from obtaining an unstoppable power.

Momotaros is warned about the demon king by Yuuto, taking back the Den-O watch in the process; the gang must travel back to 2011 to stop the Mole Imagin.

After being defeated by Oma Zi-O, Sougo arrives back in 2019 where all his friends have turned against him and his only ally is a passing through Kamen Rider.

Tsukuyomi saves Sougo from an attacking Geiz; Schwartz recruits Daiki Kaitou after he's caught stealing from Another Zi-O.

Schwartz reveals to Tsukuyomi that they are siblings; Ora and Heure are relieved of their Timejacker duties.

Kamen Rider Aqua arrives in a prototype Time Mazine to take Geiz and Tsukuyomi back to the future; Heure and Ora seek shelter with Sougo after being attacked by Another Drive.

Geiz doesn't trust Heure after finding out that Ora is Another Drive; Schwartz uses his powers to summon Kamen Rider Eternal.

Sougo and crew attempt to make a deal with the newly revived White Woz to save Geiz.

Sougo is given an ultimatum regarding his path by Schwartz and takes Tsukuyomi to visit her own time; enemies that should be defeated because of the previous Kamen Riders are now all returning.

Tsukasa has a plan to stop Schwartz, but it doesn't involve Sougo surviving the outcome.

Tsukuyomi has transformed into a Kamen Rider and the final battle has begun.