When his fiancée, Helen (Bianca Lawson), breaks up with him at their engagement party, Quincy (Jamie Foxx) is devastated. He attempts to exorcise his demons by writing a heartfelt letter to Helen, but it mutates into a manual on the proper way to terminate a relationship. Thus, The Breakup Handbook is born. His book becomes a nationwide bestseller, and even his old boss (Peter MacNicol) seeks out Quincy for advice on ending his relationship with his money-hungry girlfriend (Jennifer Esposito). Meanwhile, Quincy's cousin Evan (Morris Chestnut), famous for short-lived relationships, asks Quincy to help him break up with his current girlfriend, Nicky (Gabrielle Union). However, when Quincy tries to help, the sultry princess casts her spell and sends his already flailing world into its final spiral.