Ultraman Decker The earth seems to have regained peace, with the monster disasters of the past gone. As mankind's eyes turned toward further expansion into space, the scale of countermeasures against monster disasters tended to shrink. In the midst of this, a mysterious space-floating object "Sphere" suddenly flew in and began to attack the Earth, cutting off communication with the universe and turning humanity into an "isolated planet." The devil's hand approaches the daily life of the main character "Asumi Kanata". Destruction unfolds in front of you, and a giant monster finally appears. Kanata transforms into "Ultraman Decker" when he jumps into the enemy who is there now, regardless of danger. "I have no choice but to do it now!" Kanata, who got Decker's "light", decided to fight to protect everyday life, and became a new member of the new expert team "GUTS-SELECT", which was reorganized as an anti-Sphere unit. , Confronting a huge enemy with young friends!