Goro Hoshiwatari is an adolescent who joins the Yamamoto Anshin Travel agency to work off a debt after accidentally damaging their spacecraft. His driving purpose is to find his father, Daigo Hoshiwatari, who vanished fifteen years earlier during an accident involving his own dimensional tunnel prototype.

He is brave and righteous, often acting on impulse to defend others or pursue justice. His search for his father is relentless, persisting through countless obstacles and dead ends. This quest is emotionally complex, as his initial anger over being abandoned gradually shifts when he learns the truth behind the disappearance.

Goro has spiky hair often compared to a crab’s shape and wears a pair of goggles—a tragic keepsake from his father. At the agency, he is assigned maintenance and cleaning duties under exploitative conditions, yet he forges strong bonds with the crew. He holds deep, unreciprocated romantic feelings for Katsura Tenjoin, the president’s adopted daughter.

His journey brings him into conflict with space pirates and corporate rivals. Six months after the events of the first season, he and the crew are transported to an unknown universe and become embroiled in a conflict over a transportation device and an evil empire.

Goro eventually reunites with his father, discovering he was trapped in another dimension where time passed differently, leaving him physically unchanged. This reconciliation resolves their misunderstandings. Beyond the core crew, he interacts with Kanea Marigold, heiress to a rival corporation, who develops romantic feelings for him that he does not return due to his affection for Katsura.