The story is set among American and Puerto Rican street gangs in New York City's Upper West Side. Tony and Maria fall in love, despite the fact that they are associated with rival gangs - Tony with the Jets, and Puerto Rican-born Maria with the Sharks. The Sharks are led by Maria's brother, Bernardo, and the Jets by Tony's best friend, Riff. When the gangs arrange a "rumble", Maria pleads with Tony to prevent the fighting, but when Bernardo unintentionally stabs Riff to death, Tony, in a rage, kills Bernardo. He and Maria plan to run away together. Bernardo's girlfriend, Anita, agrees to help, but when she is taunted by the Jets, she invents a story that Maria has been killed by Chino, the man she was supposed to marry. Tony runs out into the street, where he is shot by Chino; in the aftermath of his death, Maria is able to finally bring all the young people together.