Larry Gigli (Ben Affleck) is a low-ranking Los Angeles mobster who is not nearly as tough as he likes to act. Gigli is a collector but ends up being soft and lets them go even if they pay half the money, rather than hurting them and letting the word spread. Louis (Lenny Venito), a higher-ranking member of Gigli's organization, commands him to kidnap the mentally challenged younger brother of a powerful federal prosecutor to use as a bargaining chip to save New York-based mob boss Starkman (Al Pacino) from prison.Gigli successfully convinces the young man, Brian (Justin Bartha) (who is staying at a center for "special" people), to go off with him by promising to take him "to the Baywatch", apparently a reference to the television show of that name, which seems to be Brian's singular obsession. Louis does not trust Gigli to get the job done right, so he hires a woman calling herself Ricki (Jennifer Lopez) to take charge. Brian has Tourette's syndrome. Ricki enters Gigli's apartment by pretending to be a new next-door neighbor who needs to make a phone call. Once in, Ricki reveals to Gigli that Louis sent her to keep an eye on him. After talking to Louis, Gigli tries to assert his dominance over Ricki, but she pushes back and tells Gigli to leave Brian alone.Gigli is attracted to Ricki, but he resents both Louis' lack of faith in him and having to take orders from a woman. Gigli puts Brian to bed on his sofa and invites Ricki to share half of his bed, professionally. Then Gigli proceeds to try and seduce Ricki with his abs and muscles. Ricki tells Gigli that she is a lesbian and hence Gigli is not her type.He is also frustrated by Brian's insistence on going to "the Baywatch" and by the fact that Ricki is a lesbian. A suspicious Detective Stanley Jacobellis (Christopher Walken) comes to the apartment to question Gigli in reference to Brian's disappearance (and the fact that this might impact Starkman's prosecution and sentencing). Gigli is worried that cops are looking for Brian and decides to leave his apartment to hide Brian someplace safe. He gets a call from his mother, who asks him to visit. Gigli has no choice but to take Ricki and Brian with him. He is further annoyed when his mother (Lainie Kazan) immediately bonds with Ricki and they team up to needle him. Gigli clarifies that Ricki is a lesbian.eventually, Gigli, Ricki and Brian go back to Gigli's apartment. Events take a darker turn when Gigli and Ricki receive orders to cut off Brian's thumb (& mail it to his prosecutor brother with one day delivery), something neither wants to do. Worse, her ex-girlfriend, Robin (Missy Crider), shows up at the apartment, accusing Ricki of changing sexual orientation. Robin attempts suicide by slitting her wrists and is rushed to the hospital, where she survives. There, Gigli sneaks into the morgue and cuts off a corpse's thumb, which he sends to the prosecutor as Brian's. Gigli and Ricki go back to his apartment, where he confesses his love and they sleep together.They are summoned to meet with the mob boss. Starkman reveals that he did not approve of the plan to kidnap a federal prosecutor's brother (as that merely enraged the entire federal law enforcement apparatus to close ranks behind their own) or cut off Brian's thumb. He nevertheless rages at them because it didn't match Brian's fingerprint, and therefore not only failed to increase pressure on the prosecutor but even undermined their credibility.Starkman then kills Louis, in retaliation for the kidnapping and associated scrutiny by law enforcement. He is about to kill Ricki and Gigli, but she talks him out of it (she says that they deliberately did not cut Brian's finger as it would have been impossible to be under the radar with a bleeding finger of a half-wit). She points out that only they know where Brian is and only, they can silence and prevent him from revealing Starkman's organization's involvement in the kidnapping.They leave Starkman's, decide to leave the mob, and discuss taking Brian back to where they found him. On the way, they discover a Baywatch-like music video filming on the beach. Brian begs to be let off there and finally they consent. Gigli calls Brian's brother at the courthouse from a pay phone and informs him where he can find his brother. Gigli convinces Ricki to take his car to escape to parts unknown; but at the last minute, she returns to pick him up (says her real name is Rochelle), and they leave town together.