In the year AD 2017 (nine years after the final episode of Ultraman Tiga), TPC has advanced beyond Earth, and has created a new GUTS team, "Super GUTS". Humans have begun terra-forming Mars and other planets in what is known as the "Age of the Neo Frontier". One day, however, the Neo Frontier is attacked by an alien race known as the Spheres. Shin Asuka has just joined Super GUTS and is in the middle of training maneuvers above Earth's atmosphere when he and his comrades are attacked. He proves himself in battle and can hold his own against ace pilot Ryoh. However, his ship is damaged, and he ejects, after which he encounters a shining light. It is then that a new giant of light merges with the bewildered Asuka, saving his life. When the Spheres enter Mars' atmosphere and merge with the Martian rocks to form monsters, Asuka again participates in the battle, now equipped with a mysterious device known as the "Reflasher". Upon the Sphere's new attack, Asuka suddenly transforms into a colossal giant and manages to protect Mars from a group of monsters sent by the Spheres. The members of Super GUTS quickly catch on that this giant being is not Ultraman Tiga, but a new giant of light, "Ultraman Dyna".