All Marty (Josh Hamilton) wants is a regular life, but nothing goes as planned when he brings his fiancée, Lesly (Tori Spelling), to meet his far-from-normal family. His beautiful but crazy twin sister, Jackie-O (Parker Posey)—who is strangely attached to Marty—becomes dangerously jealous of his new love. Meanwhile, their younger brother, Anthony (Freddie Prinze, Jr.), puts the moves on Lesly the first chance he gets. As their visit spins wildly out of control, Marty and Lesly realize that his mother (Geneviève Bujold) may be able to hide the kitchen knives, but she can't hide the family's shocking secrets.