The story takes place in the time and space of the future, when the outbreak of canine flu led to the dog exile bill issued by the mayor (voiced by Nomura), which put all the dogs in the city on the "garbage island" and left them to fend for themselves, and the mayor's guard dog spot (played by Levi Schreiber Liev Schreiber) bore the brunt. In this way, the dogs who had been kept at home became stray dogs looking for food in the garbage. The Leader (voiced by Brian Cranston Bryan Cranston), the Sovereign (voiced by Edward Norton Edward Norton), the Boss (voiced by Bill Murray Bill Murray), the Duke (voiced by Jeff Gao Buren Jeff Goldblum) and the King (voiced by Bob Balaban Bob Balaban) are five stray dogs on the island that usually act together. One day, the mayor's adopted son Atari (voiced by Keyu Rankin Koyu Rankin) suddenly landed in a plane on the island, where he was looking for his best friend for life.