Rusty Griswold takes his own family on a road trip to "Walley World" in order to spice things up with his wife and reconnect with his sons.

When his boss is killed, Detroit cop Axel Foley finds evidence that the murderer had ties to a California amusement park called Wonder World. Returning to sunny Beverly Hills once more, Foley reunites with Detective Billy Rosewood to solve the case. Along with Billy's new partner, Detective Jon Flint, they discover that Wonder World is being used as a front for a massive counterfeiting ring.