To help get Brian's life in order, Stewie and Brian swap bodies using a machine that Stewie invents, but chaos quickly ensues around Quahog when the machine goes haywire.

Quagmire's most treasured body part gets cut off in a freak accident and he is forced to learn how to live without it. Meanwhile, Stewie and Brian search for Mort after learning there is a $10,000 reward for turning him into the police for his involvement in a drug scam.