Takeru Tenkuji strives to be a Ghost Hunter just like his late father, Ryu Tenkuji. On his 18th birthday, he receives a Ghost Eyecon as a present from his late father's spirit. However, a mysterious monster appears, demanding that Takeru hand the Eyecon over. Takeru boldly confronts the monster, but...

Takeru has been revived from the dead and has obtained the power to transform into Kamen Rider Ghost. However, he now has only 99 days to obtain the Eyecons of 15 heroes. Akari, who can't cope with the lack of any logical and scientific sense this situation makes, is called by her professor to where another strange event has occurred. Meanwhile, Onari, knowing that the Gamma are targeting the hero Eyecons, instructs Takeru to go wherever strange events happen and sends him to the same place. Takeru finds out from the Hermit that the next hero to appear is Thomas Edison. However, he has no clue how to summon him. Meanwhile, the mysterious man in black is meeting with an inventor. What is his objective now?!

The next hero seems to be Billy the Kid. Takeru immediately gets Sennin's clue and at the same time, a new client comes to the Laboratory saying that something is wrong with their best friend. At the same time, Narita and Shibuya bring information of a sighting of the Mysterious Man. Akari and Onari follow the clue to the Mysterious Man and see him talking to Specter. The man, whose name is Saionji, talks about "what happened 10 years ago..."

All the inhabitants of the apartment building the friend lives in seem to be acting strangely as well. Takeru investigates and a Gamma appears. Takeru transforms into Ghost and fights but Specter appears. Takeru, who now has lost all fear, confronts Specter as well.

The Fukami siblings, Makoto and Kanon, are approached by Alain and Jabel. Makoto attempts to fight Jabel but is overwhelmed, which results in Kanon being kidnapped. Knowing that he can't beat Jabel as he is, Makoto tries to use the Eyecon of the "Escape King", Houdini, even though it never let him use its power before.

Gammaizer Gravity begins to attack alongside Gammaizer Fire, causing significant damage. Alain attempts to defeat Gammazier Fire with a kamikaze-like ability of the Necrom system to protect Takeru, but is knocked out of his transformation at the last moment. The unexpected happens when Gammaizer Gravity both defeats Ghost, and destroys his Ore Eyecon, causing him to vanish.

Takeru's absence saddens his friends and allies and while they discuss how to revive him, the Gammaizers reappear. Akari opens a portal to send them to another world, but the plan fails when they managed to escape and soundly defeat the other riders.

Akari and the others vow to not give up, and their resolve and emotions not only revive Takeru, but grant him the Mugen Eyecon. Takeru returns with new strength and destroys Gammaizers Gravity and Fire. Is this new power only a temporary halt to Takeru's death, and can it permanently destroy the Gammaizers?

The Dream World Takeru and the others were investigating was another one of Igor's schemes. Jiro, brother of Akari's professor, Yuichi Katagiri, insists that he won't leave the Dream World. The brothers' squabble catches the attention of the Grimm Eyecon and the Brothers Grimm themselves start having a discussion about fun. Due to this, Grateful Damashi can no longer be maintained and the Eyecon is stolen. A new Gammaizer has appeared as well.

In the meantime, Makoto and Alain, tasked with protecting Takeru’s body, confront a Gammaizer themselves in the real world.