The Jets wait for the Sharks at Doc's store. Action is impatient, as Baby John looks at a Captain Marvel comic book. Anybodys shows up and gets in a fight with one of the Jets after he alludes to her sister being a prostitute. As Riff arrives, he ask if anyone's seen Tony, but they tell him he's not around. Anybodys asks Riff if she can help, but he rejects her, as Riff's girlfriend, Graziella, calls her an "American tragedy."
Riff tells Graziella and Velma, Ice's girlfriend, to leave when the Sharks arrive. Suddenly Officer Krupke shows up and points at Baby John. He asks the group why they're standing on the streets, and the Jets begin telling him that their home lives are awful and they dare not return home. When Krupke leaves, the boys begin singing a song about him and their bad home lives ("Gee Officer Krupke"). They act out a playful depiction of Riff going to court, where he is deemed "psychologically disturbed." Action plays the role of a "head shrinker" who diagnoses him as "sociologically sick." A-Rab plays a social worker in the song and sends Riff to a prison, deeming him "no good."
Doc comes outside and tells them to clear out. The Jets all come into the store and tell Doc what's going on with the Sharks. "Fightin' over a little piece of street is important?" Doc asks, frustrated with the rebellious hoodlums. Bernardo and the other Sharks show up, and Velma and Graziella leave. Riff signals for Anybodys to leave also, and she does so reluctantly.
Bernardo sits down with Riff, who challenges the Sharks to a rumble. When Riff says that the Sharks have been too aggressive, Bernardo insists that the Jets started it. "Who jumped Baby John this afternoon?" Riff yells, as Bernardo yells back, "Who jumped me the first day I moved here?" After Bernardo agrees, Tony comes into the store and tells everyone that the rumble can be decided by a fair fight. "Best man from each gang to slug it out!" Tony says, and Bernardo starts to agree, but everyone else objects. Riff extends his hand and they shake on it, but Bernardo misunderstands and thinks he will be fighting Tony. When he realizes that he might not be fighting Tony, Bernardo is disappointed, but they are interrupted by the arrival of Lieutenant Schrank.
The members of the two gangs pretend to be friendly as Schrank comes in. He goes into a monologue about how he might get a promotion if people learn that the two gangs are getting along, before spewing some racist thoughts about the Puerto Ricans and the fact that they are ruining the neighborhood. Schrank tells Bernardo to leave, and Bernardo stares at him menacingly. "It's a free country, and I ain't got the right. But I got a badge. What do you got?" Schrank says. The Sharks leave, whistling "My Country 'tis of Thee."
Schrank asks the Jets where the rumble is going to be, but everyone is silent. He baits each of them, but they stay silent. Everyone but Tony and Doc leave. Tony tells Doc that it's going to be a fair fight and that everything will be alright. He tells Doc that he's in love with a Puerto Rican girl and Doc gets worried.
The next day, Maria tries on hats at Lucia's dress shop. "What has Chino done to her?" one of the girls asks, and Maria tells them she has a secret. Playfully, Maria wraps herself in some fabrics and sings about how happy she is ("I Feel Pretty"). Lucia interrupts the song for scolding the girls for not working harder. The girls leave, except for Anita and Maria.
Anita asks Maria to leave with her, but Maria says she will lock up. Anita tells Maria that she's going home to take a bubble bath, because she has a date with Bernardo after the rumble. Maria is surprised to hear that there is a rumble, and says, "Why do they always fight?" Anita tells her that they have to get rid of their excessive feelings, just like the way they dance, and implies that Bernardo is always very desirous and sexual after a fight.
Suddenly, Tony rushes in to see Maria, and Anita gives her a knowing glance. Maria tries to make up an excuse that Tony is there to deliver aspirin from the drugstore. "You'll need it," Anita says, knowingly. Maria asks Anita not to tell anyone anything, and she agrees, before telling Maria to come home in 15 minutes. Anita leaves.
Maria tells Tony to go and stop the rumble that night. Tony is optimistic that things will be alright, but Maria insists that he must stop it.
The Jets and the Sharks are tough, making big threats and getting mixed up in some dangerous situations, but it is also very apparent that they are, before anything else, kids. They are naive and bright-eyed as any other youths, in spite of their rough upbringings and difficult lives. Baby John reads a comic book as they wait for the Sharks, and other little details show the ways that the characters are more innocent than they appear. These are kids forced to grow up too fast, forced into precarious and dangerous situations by their circumstances.
The characters' innocence is partially revealed through moments of song. The Sharks have an ecstatic musical moment when they sing about the pros and cons of living in "America" and the Jets show their playful sides in the satirical ode to Officer Krupke. These songs are each joyous and playful, revealing the funny and lighthearted sides of the characters. In spite of their tawdry lives, the characters find joy in unexpected ways, and each gang is humanized through these musical moments. The Sharks debate the sociopolitical limitations and opportunities of immigration, while the Jets make fun of others' perceptions of them as somehow damaged by their tumultuous upbringings.
The song "Gee Officer Krupke" looks at the delinquency of the Jets through a satirical and ridiculous lens, further showing the division between the adult world and the world of youth. The Jets are self-aware in their diagnoses of themselves as misguided and neglected by their working-class families, but they also use the song as a way of revealing the deficiencies of the adult world that thinks it is looking after their best interests. In an elaborate performance, the Jets demonstrate the chain of authorities that seek to rehabilitate delinquents, showing how police officer leads to a judge leads to an analyst leads to a social worker leads to prison. They show how the various diagnoses these authorities give are also a kind of abusive misunderstanding, a way of pinning the blame on the delinquent himself rather than the system that cannot support him.
Complicating matters even further is the fact that the adult world is more prejudiced and antagonistic to Puerto Ricans than the white youth. Lieutenant Schrank is anxious to see the fighting between the Jets and the Sharks die down, but he also stokes the antagonism when he spews his bigotry against the Puerto Ricans at Doc's, complaining that they are turning New York into "a stinkin' pigsty." In moments like this, we see that the fighting and the violence between the young people is inherited from the older generation rather than generated by the kids. The reason the adults and the authorities cannot help the Jets and the Sharks is because they created and perpetuate the structures of hate and bigotry in the first place.
The film puts romance and the lushness of a traditional musical alongside the rising tensions of a divided neighborhood. We watch as Tony and Maria fall in love against a backdrop of discord and heavy adult difficulty that exceeds their ability to cope. For all the innocence and beauty of a young person's first experience of romantic love, there is also the gritty, cynical world of the neighborhood that threatens to ruin it all. Indeed, the story of West Side Story takes its inspiration from William Shakespeare's great tragedy of young lovers caught in between warring camps, Romeo and Juliet.