The play begins with Henry Reyna and his 38th Street Gang members headed to a local dance. While at this dance, they encounter their rivals, the Downey Gang. Henry’s brother, Rudy, starts a fight between the two gangs. This results in the 38th Street Gang leaving the party.
Della, Henry’s girlfriend, then accompanies him on a trip to Sleepy Lagoon, a popular hang-out spot for Chicanos. While there, Henry hears noises coming from the Williams’ Ranch, and suspects that there is a party being held there. Henry and Della decide to go to the ranch, where the Downey Gang are harassing the residents.
Mistaking Henry and his friends for the troublesome Downey Gang, a group from the Williams ranch attacks them. This attack results in the death of Jose Williams, an occupant of the Williams’ ranch. Henry and the 38th Street Gang members are soon arrested and charged with the murder of Jose Williams. Evidence clearly shows that the Downey Gang members are responsible for the death of Jose Williams, but the jury is strongly prejudiced against the 38th Street Gang members, largely because of their race. Despite the efforts of George Shearer, their lawyer, and Alice Bloomfield, a white journalist and activist, the 38th Street Gang members are unfairly sentenced to time in prison.
The boys are sent to San Quentin Prison, where they waited for their appeal to go through. During this time, Henry develops a crush on Alice despite still being involved with his girlfriend Della. George Shearer, their lawyer, is drafted to serve in the war. Henry gets sent to solitary confinement after pushing a prison guard. Throughout the events of the play, he is visited by a vision of El Pachuco, the archetype of the zoot suit-wearing Chicano.
While the gang is in jail, the Zoot Suit Riots break out all over Los Angeles and neighboring cities. The boys are eventually released from jail, winning their appeal. The end of the play presents three potential fates for Henry. In the first path, Henry goes back to jail and dies due to stress. In the second path, Henry serves in the war and dies as a hero serving his country. Finally, in the third path, Henry gets married and has children.