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!

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!

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!!