The Jets and the Sharks have one of their fights over a little piece of the territory that has been allocated to them by the system, only to be visited by Lt. Schrank and Ofcr. Krupke, who, after a lecture, roughly orders the Sharks out of there, after breaking up the fight. The Jets do not want Bernardo and the Sharks on their territory and are determined to keep them out, at all costs. After debating what to do, Riff and the Jets decide to challenge Bernardo (the Sharks gangleader) and his Sharks to a rumble. Tony, the founder/ex-leader of the Jets, who is looking for something beyond the streets and gangsterism, has taken a full-time job at Doc's Candy Store, doesn't know what he's looking for. Despite protests from some of the other Jets, Riff, an old buddy of Tony's who's taken over the Jets leadership since Tony left the gang, goes to Doc's store and calls upon Tony to be his lieutenant and help him out during the rumble. Tony declines, but is persuaded by Riff to come to a dance that's being held at a local gym, stating "Who knows? Maybe what you're looking for will be twitchin' at the dance tonight!"
Meanwhile at the Bridal Shop where both Anita and Maria work as seamstresses, Anita, the fiery girlfriend of Bernardo, is altering an old communion dress for Maria to wear to the dance that night. Maria, the sister of the Shark gangleader, Bernardo, has been brought from Puerto Rico to the Continental United States to marry Chino, also a Shark member who's Bernardo's right-hand man, but it doesn't work out, as we shall see. At first Maria balks at wearing a white dress, and asks that the dress be dyed red, and that the neck be lowered an inch or so, but, Anita stands firm, telling Maria that she doesn't have to wear it or come to the dance that night. Reluctantly, Maria tries on the dress, loves it, and it all excited about coming to the dance as "the beginning of her life as a young lady of America."
Bernardo and Chino call on Maria and Anita to take them to the dance at the gym. Everybody's dancing and enjoying themselves, but when Glad-hand, the social worker on call that night, tries to engage the Jets, the Sharks and their girls in a get-together dance, it fails miserably. The dance then turns into a competition between the Jets and Sharks. Tony and Maria see each other across the room, begin to dance together, after falling in love at first sight, but are pulled up short by an enraged Sharks gangleader, Bernardo, who angrily orders Maria home, despite her protesting. Riff intercepts Bernardo, stating that he wants him and the Sharks to meet the Jets at midnight, at Doc's Candy Store for a war council. Bernardo agrees. Pre-existing tensions and hostilities between the Jets and Sharks begin to escalate sharply when Maria and Tony get together, which eventually leads to a deadly show-down.
When Anita, Bernardo, the Sharks and the rest of their girls come home from the dance, they have a little party on the rooftop, and an argument ensues between the Sharks and their girls about the virtues and vices of life in America and the immigrant experience.
Tony goes to Maria's apartment, throws afew pennies at the window, and Maria appears. She and Tony are on the fire escape talking, and they agree to meet at the Bridal shop, where both Maria and Anita work as seamstresses, at closing time the next evening, at around six o'clock.
Riff, the Jets, and Anybodys, a girl who's a tomboy and vying for acceptance by the Jets, are all waiting outside Doc's Candy Store, where Krupke and another police officer stop by, warning the Jets not to cause trouble. Ofcr. Krupke is lampooned by the Jets as soon as he leaves. The Jets enter the Candy Store, the Sharks arrive, and, despite Doc's urge for the boys to just talk it out, the war council for the rumble proceeds. Velma and Graziella, who are the girlfriends of Ice and Riff, are also in the store, but are ordered out by Riff. Anybodys hides, only to be spotted out by Riff and ordered out of the Candy Store, despite a "let me stay" look on her part. Unlike Graziella and Velma, however, Anybodys shoves some of the Sharks like a big tough guy, much to the Sharks' amusement.
Tony, who has been working at Doc's store, comes in and suggests a "fair" fight, in which the best man from each gang would slug it out with fists. After a dispute that culminates in the exchange of racial and ethnic epitats, the war council begins. Although Bernardo hoped to fight Tony, Riff intercedes and picks his lieutenant, Ice, to fight Bernardo, much to Bernardo's disappointment. A fair fight is agreed upon, after the rumble is set for tomorrow, after dark, under the West Side highway. Riff and Bernardo, the two leaders, shake hands to seal the commitment. Shortly thereafter, Lt. Schrank comes in to the Candy Store, roughly banishes Bernardo and the Sharks, and then begins to grill the Jets about the rumble, and its whereabouts, etc.
When the Jets refuse to give Lt. Schrank any information, Schrank begins to insult the Jets for their familial and ethnic backgrounds, indicating that he doesn't clearly doesn't like the Jets much better than he likes the Sharks. Action, meanwhile, flies into one of his rages, and tries to go after Lt. Schrank, but the other Jets restrain him. The Jets all leave, on the order of Tony.
The next night is a big evening, which will mean different things and have markedly different results for different people. Maria happily and excitedly prepares for her meeting with Tony, and the other girls are either making fun of her for acting kind of vain, or are sort of cheering her on. Anita and Bernardo make big plans for some quality time after the rumble. Tony and Maria meet at the Bridal shop as planned, much to the disapproval of Anita, who admonishes Maria to be home in 15 minutes. Anita leaves to get ready for the evening, and Maria and Tony stage a mock wedding, with the use of the various shop mannequins and bridal clothing in the shop, pledging their love. On hearing about the Rumble, which Tony plans to steer clear of, Maria begs him to go and stop the rumble, which has disastrous results, as we shall see. The Jets and Sharks get ready for the rumble, assembling on a rooftop and gathering the necessary tools and information.
The Jets and Sharks meet at a secluded place under the West Side Highway, and Bernardo and Ice begin to fist-fight. Tony appears, and tries to stop the rumble, but to no avail. Riff and the Jets are angered and puzzled with Tony, while Bernardo insults Tony and begins roughing him up, after Tony tries to shake hands with Bernardo, who, infuriated by Tony's interest in his sister, repudiates him violently, and calls Tony an ethnic slur. Riff intervenes, belts Bernardo, and the two leaders begin to fight--with switchblade knives. Tony tries to stop Riff, but is held back by two Jets; Ice and Tiger. Just as Riff is about to knife Bernardo, Tony breaks free, tries to stop Riff, and Riff is knifed to death by Bernardo, handing Tony his knife as he falls down dead. In anguish and rage, Tony quickly charges forward, stabbing Bernardo and killing him. The Jets and Sharks immediately engage in battle, fleeing the police at the wail of a siren. Meanwhile, a confused Tony, blinded by searchlights and realizing what he's done, tearfully calls Maria's name, but nothing comes of it.
Baby-John, the youngest and least mature member of the Jets, hiding on a West Side tenement rooftop, has been moved to tears by the killings, and is found by his buddy and fellow Jet, A-Rab, who comforts him. They give the soft Jets whistle, and are found by Ice (who's assumed leadership of the Jets since Riff's death during the Rumble.) Graziella begins to weep over Riff's death, but is comforted by Velma. Action begins to lay into Baby-John for being scared, but A-Rab comes to Baby John's defense, and they begin to scuffle. A man in an apartment above the garage, awakened by the noise, throws something down at the Jets, scattering them, and ordering them to go home. Action tries to challenge the man, but Ice orders all the Jets inside the garage, where they're advised to keep cool, despite their determination to wreak revenge on the Sharks.
Unaware of what has just happened, Maria waits on their tenement rooftop for Tony's arrival.
Instead, Chino stops by to tell Maria that Bernardo has been stabbed to death by Tony. Maria refuses to believe it, but Chino convinces her that it really did happen. Meanwhile, Tony climbs through Maria's bedroom window into her bedroom as she's doing a "Hail Mary" in Spanish, and tries to lift her in his strong arms, but Maria begins beating him and yelling "Killer, killer, killer, killer!" at Tony. She and Tony rest in Maria's bedroom.
Tony and Maria are asleep in Maria's bedroom, when Anita comes knocking on Maria's door. Although she hears voices in Maria's room, Anita doesn't know what they're saying. Tony then climbs out Maria's bedroom window and out into the street, where he is found by Anybodys, who tells him to go to Doc's Candy Store andhide in the cellar, which Tony does. Anita, however, immediately figures out that Maria has hidden Tony in her bedroom, and she angrily berates Maria for allowing Tony near her. Maria, however, emphasizes her love for Tony, despite Anita's grieving over Bernardo's death, and reluctantly comes to terms with Maria's love for Tony.
Lt. Schrank, meanwhile, pays Anita and Maria a visit, to question them about the events that had taken place the night before, at the dance. When he mentions that Bernardo got into an argument because Maria danced with the "wrong" boy, Maria states that it was another boy from her country, named Jose. She then pretends that she has a worsening headache, in order to get Schrank off the subject, and then requests Anita to go to Doc's Candy Store to warn Tony that Chino is gunning for him. Reluctantly, Anita agrees, but the results are disastrous.
The Jets, including Anybodys, are all assembled in Doc's Candy Store, determined to protect Tony from Chino. Meanwhile, Anita comes in, hoping to go down to the cellar to warn Tony that Chino's gunning for him and to help protect him. The Jets, however, partly out of fear that Anita will give Tony's hiding place away to Chino, and partly out of prejudice against Anita due to her being Puerto Rican, rebuff her offers to help protect Tony, begin to insult her, and they rough her up, until Doc comes in and stops them. Angry at being harassed, humiliated and insulted by the Jets, Anita retaliates by relaying another message to Tony; that Chino has found out about Tony and Maria and shot her dead. She bitterly denounces the Jets, saying "Bernardo was right! If one of you was bleeding in the street, I'd walk by and spit on you." The Jets are silenced, Doc orders them out of the Candy Store in exasperation, and then goes down into the cellar to relay Anita's message to Tony.
Tony is excited, waiting for Maria, and begins telling Doc about him and Maria's going to the countryside together, having lots of kids and naming them all after him, until Doc smacks Tony to wake him up, after giving him some money. Doc pointedly tells Tony that Maria has been shot and killed by Chino after he'd found out about her and Tony's relationship. Devastated, Tony runs from Doc's cellar into the street, calling for Chino to come and kill him too. Anybodys appears from the shadows and warns Tony to leave, but Tony rebuffs her and continues to call for Chino to come and get him. Then Maria appears, she and Tony embrace for a brief moment, and then Chino appears and shoots Tony dead. He dies in Maria's arms.
The rest of the Jets and Sharks arrive at the playground, and are ordered by Maria to stay back, as they're clearly about to clash once more. She then conveys a strong message to both the Jets and the Sharks; that they've killed Bernardo, Riff and Tony with their hatred. She then orders Lt. Schrank not to touch Tony's body. Several Jets and Sharks come together to carry Tony's body off, and, for at least a fleeting moment, seem united in an understanding of tragedy. Chino, meanwhile, has been arrested for Tony's murder, and is escorted to and taken away in a waiting police car.
West Side Story is a beautiful film, with a concise (albeit somewhat double-edged) message; The senselessness of racial/ethnic hatred and the violence that often ensues as a result, and yet, reconciliation between people, as difficult as it may be, is still possible, nonetheless.