Several years after the world was saved by Ultraman Trigger, mankind has turned its gaze skywards to space.

Suddenly, unidentified orbs dubbed “Sphere” invade! They begin their attack on Earth. Asumi Kanata, son of a rice cracker grocer, witnesses this tragedy unfold before him, and vows to protect the people. As he does, he is enveloped in light!

And the new form he takes on... Is it a new Ultraman?!

Kanata enters the TPU training school, and begins marching drills with classmates Ichika and Ryumon. However, he and Ryumon start butting heads after a difference in opinion... Just then, Deathdrago appears before them! Will Kanata pull through this deadly situation? And can the three of them become members of GUTS-Select?!

A new aircraft GUTS Hawk deploys to GUTS-Select. To fully utilise its power, GUTS-Select need to coordinate with the Hawk's AI pilot, HANE2! But communicating with HANE2 proves a difficult task for Kanata and his team mates .... The sudden appearance of Gomora only adds to their difficulties. Don't give up, Decker! Use your new power to save the day!

A mysterious giant capsule suddenly appears in a forgotten onsen (hot spring) town! Although, the mayor is taking pictures and looks oddly happy? Mons-Ahgar appears to throw GUTS-Select and the town further into chaos! Their hopes to save the day lie in promising new technology, and so Kanata and crew turn their efforts into combining the two GUTS aircrafts into one: the GUTS Gryphon!

Eleking suddenly appear in the city! Where Eleking appears, Ichika encounters a mysterious young girl, Yuko. Eleking has been going around and stealing electricity to snack on, but are the two connected somehow?

After she meets Yuko, Ichika doesn't seem to be her usual self. Where will Ichika's sincere feelings take her?

The Sasamedake flower blooms. It is said to be the harbinger of disaster! Then, a golden rainbow appears in the sky! As if responding to its call, a subterranean monster appears! Ryumon is injured as this unprecedented situation unfolds. Kanata tries to cheer him up, but....what lies at the end of Ryumon's gaze?

A mysterious energy is detected underground. Could it be?! The power of darkness defeated ten years ago?! As Kanata and crew are stunned with shock, from the sky the legendary giant himself lands before GUTS-Select; Ultraman Trigger! Decker and Trigger, the two Giants of Light begin their fight against the power of darkness!!

A mysterious giant plant appears and the pollen it spreads lures people into a world of dreams! But it looks just like R'lyeh, the plant Kengo Manaka grew to bring smiles to the people of Mars...?!

A familiar face shows up as Kengo, Kanata, and crew try to take control of the situation, and the GUTS-Select joint extermination operations begins!

Kanata meets a young girl, Mika. She says she wants Kanata/Ultraman Decker to fight her father?!

Her father is the Space Martial Arts Champion, Grace...

Will the duel between Decker and Grace take place? And how will it end?!

The mysterious monster Neomegas appears suddenly in town, defeats several other monsters, and leaves. Vice-Captain Kaizaki tries to find out what's really going out, when she remembers the words of her mentor. The terrifying true meaning behind those words reveals itself before Kanata, the GUTS-Select team, and Ultraman Decker!

Finally! Finally!! GUTS-Select are given with new equipment in the form of a robot! It's name is the "TerraPhaser"!! Everyone is excited to meet the robot they'd been waiting for, but for some reason monsters appear every time they try to test a boot-up sequence!! As Ultraman Decker holds off the monsters, can the team safely start-up the TerraPhaser?!

The remaining cells of Neomegas are used to create Sphere Neomegas, and Ultraman Deckker and GUTS-Select struggle against it's overwhelming power. Kanata and the others are left powerless in this desperate situation, but pulling together all of their strengths around the TerraPhaser, their counter attack plan begins!

The Nursedessei's systems suddenly go down. A power-outage?! Who appears in this emergency but Maruluru of the previous GUTS-Select team! Kanata and the crew are grateful for their seniors' timely appearance, but Marluru's sharp tongue leads to heated outbursts! Will Kanata and crew figure out how to work with Marluru and safely restore power to the Nursedessei?!

Ultraman Decker and the TerraPhaser prove to be the ultimate duo! Kanata is overjoyed when the pair's successive victories increase their popularity around the world. Suddenly, the Spheresaurus appears again at the spaceport! It seems to be even stronger than last time. As the ultimate duo faces against the monster, a disturbing shadow begins to move...

Kanata and the crew of GUTS-Select are shaken by an unforeseen event... Just who is the mysterious figure that appears before Kanata?! When the true face behind the sphere and the truth about Ultraman Decker are revealed, a dynamic miracle form appears!!

"Humanity must not venture into space..." Kanata and the others struggle to take in those words, but just then the small monster Spinny appears, and a TPU all-member operation begins to capture it. After all of their plans to capture it fail and Spinny makes fun of him, Kanata vents by saying something horrible to Ryuumon...

Captain Murahoshi is under investigation?! The Director of the TPU's Internal Affairs, Agent Nigel, suspects Captain and Agams might be working together. Kanata is shocked, but Nigel shows no mercy and looks for any suspicious acitivity from Murahoshi. Why doesn't Nigel trust Murahoshi? Is there any way to clear Captain's name?!

A sudden sinkhole appears in the city. Analysis shows it was caused by something beyond an average monster... Kanata, Ichika, and Ryumon head down to investigate where they encounter a mysterious shadow. Suddenly, Agams shows up again! Can Kanata keep his promise to save Agams?

Kanata a.k.a. Ultraman Decker is thrown into another dimension by the extradimensional being Yapool! Just where in space has he been sent to?

An incident of an attacking from an unidentified monster takes place in a modern city, built where it which was once an ocean, Wadatsumi City!! Kaizaki and Ichika are immediately sent to investigate. The pair find a suspicious old woman, a mysterious girl, a crowd wearing peculiar masks, and a strange green creature. Is this a place where mysterious events gather?!

The S Plazma fusion reactor is a new technology in development. The tremendous energy it could produce has the potential to allow humanity to reach the speed of light. However, this unknown energy source is concealed as a secret... Monsters are born, Agams' shadow squirms, and a truth is revealed. How will Kanata react to this crisis?!

Fugitive Agams suddenly reaches out to GUTS-Select and Captain Murahoshi is called to Agams’ hideout alone… Finally, Agams reveals the truth of the shocking events from the future timeline?! What does he mean by “Earthlings’ crime”? Can Kanata and GUTS-Select finally take Agams into custody?!

Agams is an entirely different person after his fight with Decker. Kanata searches how to save Agams from himself, meeting with the captured fugitive. They have a peaceful talk for the first time in a while gives Kanata a glimpse of Agams’ true feelings… But suddenly Sphere attacks, ruining the moment, and then an ominous, great shadow appears?!

3 hours left until the Sphere Barrier starts to shrink. The 3 hours is the last hours of hope for humanity! To destory the Sphere Oblelisks, Kanata and GUTS-Select start a joint operation with TPU.

However, the Terraphaser stands before them...!

What will Kanata do to save Agams!?