Deuce Bigalow, an insecure fishtank cleaner (aquarist), is fired for cleaning the tank at a public aquarium in the nude. Deuce is unsuccessful in attracting women, so he attempts to keep himself busy at work. On a house call, he meets an Argentinean male prostitute Antoine Laconte. Antoine is going on a business trip, and so asks Deuce to care for his sick lionfish and protect his home while he is away. Deuce accidentally sets Antoine's kitchen on fire when trying to make a grilled cheese sandwich in the toaster, and breaks an expensive fish tank.
Gigolos in Europe are being terrorized by a serial killer. In Malibu, California, Deuce Bigalow's wife Kate has died from a shark attack, and Deuce is invited by his former pimp T.J. Hicks to Amsterdam. Deuce goes to take his mind off of Kate.