A wish made with a different set of Dragon Balls turns Goku back into a child. Those balls then scatter across the universe, and Earth faces destruction unless they are recovered within a year. Goku sets out with Trunks and his granddaughter Pan on a search that takes them from one unfamiliar planet to another.
The child's body belongs to a fighter with a long adult history, while the journey puts three generations into one small travelling party. Recovering the balls requires transport, negotiation and practical escapes as well as fighting. GT is its own anime-original branch after Z, rather than a retitled season of Super.
Pan takes the forward seat while Goku and Trunks crowd into the space behind her. The ship interior gives their shared journey a close, everyday scale beside its enormous route through space. They must live and travel as a group while searching; the problem of getting to the next place exists alongside the battles awaiting them there.