When Peter and the guys try to salvage a sunken Mercedes-Benz, Peter half-heartedly promises a favor to a helpful dolphin. Soon the dolphin moves to Quahog, outstays his welcome at Peter's and moves into Cleveland's house across the street. Peter tries to reunite the dolphin with his ex-wife in hopes that he'll return to the ocean, but his plan backfires and the whole dolphin family moves into Cleveland's.

When Peter and Chris go away to fat camp, they cross paths with a serial killer who targets overweight kids. Meanwhile, Stewie is traumatized by the frightening cover of a Queen album.