Stage directions tell us that "the giant facsimile of a newspaper front page serves as a drop curtain" and "The huge masthead reads: LOS ANGELES HERALD EXPRESS Thursday, June 3, 1943. A headline cries out: ZOOT-SUITER HORDES INVADE LOS ANGELES. U.S. NAVY AND MARINES ARE CALLED IN."
As the Act 1 Prologue begins "a switchblade plunges through the newspaper" as the song "Perdido" by Duke Ellington plays. El Pachuco comes out from behind the curtain, wearing a zoot suit. "He is transformed into the very image of the pachuco myth, from his pork-pie hat to the tip of his four-foot watch chain." After speaking a few lines of Spanish, he speaks in English, welcoming the audience to the play, and telling us that it is "a construct of fact and fantasy." He describes himself, El Pachuco, as "a mythical, quizzical, frightening being/precursor of revolution/Or a piteous, hideous heroic joke/deserving of absolution?"
Scene 1. Zoot Suit. A barrio dance in the 1940s, where members of the 38th Street Gang, including Henry Reyna (21) and Della Barrios (20) are partying. There is also a sailor named Swabbie and his Japanese-American girlfriend Machuka. El Pachuco sings a song about the zoot suit while couples dance.
A rival gang, the Downey Gang, enters and challenges the 38th Street Gang. Tensions mount as the music continues.
Scene 2. The Mass Arrests. The dance is interrupted by sirens. Detectives run onstage, as Lieutenant Edwards fires a revolver into the air. The cops round up some of the gang members, including Swabbie and Machuka.
Members of the Press then enter and announce the breaking headline. "Monday, August 2, 1942. The Los Angeles Examiner Headline: Death Awakens Sleepy Lagoon. L.A. Shaken by Lurid 'Kid' Murder." Lieutenant Edwards then reads the press release from the Los Angeles Police Department: "A huge showup of nearly 300 boys and girls rounded up by the police and sheriff's deputies will be held tonight at eight o'clock in Central Jail at First and Hill Street. Victims of assault, robbery, purse snatching, and similar crimes are asked to be present for the identification of suspects."
Sergeant Smith then pulls Henry out of the lineup and throws him on the floor. Scene 3. Pachuco Yo. When Smith leaves Henry on the floor, Pachuco comes towards him and tells him that the city is cracking down on Hispanic gangs. "They're screaming for blood," he says. Suddenly, Henry gets very anxious about being locked up, but Pachuco urges him to stay cool. He warns him that the mayor of Los Angeles is waging a war on Chicanos, and tells him that he will no longer be eligible for military service after his time in jail. Henry asks for a cigarette, which Pachuco hands over, advising the gang leader to stay strong and fight back against the injustice.
Scene 4. The Interrogation. Lieutenant Edwards tells Henry that he knows why he's been arrested, and Henry says, "Yeah, I'm Mexican." Edwards replies, "Don't give me that. How long have I known you? Since '39?" and remembers arresting him for stealing a car. Edwards then apologizes for the arrest, remembering that it was Henry's father's car, but tries to soften it by reminding Henry that he helped set up the youth club that eventually became the gang.
"This is the wrong time to be antisocial, son. This country's at war, and we're under strict orders to crack down on all malcontents," says Edwards, and then congratulates Henry on getting accepted by the Navy. Sergeant Smith alludes to the fact that Henry won't be able to start with the Navy tomorrow, but Edwards says he will let Henry go if Henry tells them about the gang fight last Saturday night at Sleepy Lagoon. "Don't tell 'em shit," Pachuco advises Henry, as Henry feigns ignorance.
"I've got a statement from your friends that says you were beaten up. Is that true? Were you and your girl attacked?" Edwards asks, but Henry says nothing. Smith tells Henry that they have enough information on him to indict him for the murder of José Williams, but Henry says he's never heard of them. "Forget it, Lieutenant," says Smith, "You can't treat these animals like people." Edwards tells Smith to shut up, and gives Henry one more chance to confess something, but Henry refuses.
Smith beats Henry with a rubber sap, causing Henry to pass out. Suddenly, Dolores, Henry's mother, appears in a spotlight upstage. She then is seen "folding newspaper sheets like clothes on a clothesline." The play travels back in time, to the previous Saturday, the night of the Sleepy Lagoon murder. Dolores calls to Henry, inviting him to dinner, but Henry tells her he has to pick up his girlfriend, Della, and go to the dance. Dolores wants to know why Henry likes wearing his zoot suit so much, and worries that the police don't like them, but Henry comforts her, telling her that he will be wearing a Navy uniform soon enough.
Playwright Luis Valdez creates a strong sense of atmosphere and context in his stage directions. Before anyone has even spoken, he describes a striking image—instead of a standard theater curtain, the curtain in Zoot Suit ought to look like a giant front page of a newspaper, complete with a headline to transport the audience back to a specific time in American history. No sooner has this image appeared, than Valdez stages its destruction for the entrance of the mythic El Pachuco, who is a figment—a legend—rather than an individual man, a metaphorical leader of the Chicano sub-culture portrayed in the play.
El Pachuco sets the tone for the play, giving a poetic account of his own identity. After he speaks some lines of Spanish, he addresses the audience in English and breaks his character to tell them, "I speak as an actor on the stage./The Pachuco was existential/for he was an Actor in the streets/both profane and reverential." In this moment, the actor playing Pachuco identifies himself as an actor in order to show how Pachuco is an allegorical presence and a mystical entity more than a literal man; by calling attention to the theatricality of the figure, playwright Valdez helps the audience see the mystical elements of the plot.
As the main plot of the play unfolds, we see that the central narrative concerns the tension between the 38th Street Gang and the Downey Gang. These were real gangs that existed in Los Angeles, starting in the 1920s. Before we know much about the tension between the two gangs, we see them at a dance, working out this tension to the music provided by Pachuco. Through dance, the members of the two gangs broadcast their dislike for one another, and a fight breaks out at one point.
No sooner has the play started than the protagonist, Henry, is locked up for a murder. El Pachuco appears to him in his cell and tells him that the police are cracking down on pachuco gangs, and that they have a prejudice against him because he is a gang leader. While Henry did not commit the murder in question, the police force does not approve of the presence of gangs in the city, especially not a Hispanic one, and they need someone to pin the crime on.
The underlying attitude leading the police to wrongfully arrest and indict Henry is racism. Lieutenant Edwards and Sergeant Smith, two white law enforcement professionals, exhibit deep prejudices against Henry, and rather than try to understand what happened at Sleepy Lagoon, they infer based on speculative information that he is the one that killed José Williams. When Henry remains silent after getting accused, Sergeant Smith says, "Forget it, Lieutenant. You can't treat these animals like people." In this moment, we see that racism towards Hispanics is built into the criminal justice system, and the men charged with protecting the city harbor hateful prejudice towards the citizens living in their neighborhood.