Brian convinces Stewie to teach him how to invest in the stock market after learning Stewie has a knack for making money from it. Meanwhile, Peter, Quagmire, Cleveland, and Joe look after the Drunken Clam while Jerome is away.

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.