In the opening of the play, the stage directions only say that the members of the Jets are "enjoying, loving their home." However, the 1961 film version opens with the Jets' leader, Riff, a "glowing, driving, intelligent, slightly whacky" teenager, in close-up snapping his fingers. As the camera shot widens, we see the other Jets gang members—Diesel, Baby John, A-Rab, Snowball, and Action, all white Americans—sitting with Riff on a basketball court also snapping their fingers.
Their joviality continues as they dance through the basketball court and onto the street. It is not until they meet the leader of the Sharks, Bernardo, that their mood darkens. Suddenly they stop dancing and start to circle and taunt him.
Eventually, Bernardo escapes and meets up with his own gang. The Sharks also begin to snap their fingers, but this time in an aggressive and impatient manner. The three of them walk into the Jets' territory and confront two of the Jets outside a fruit stall. However, other members of the Jets see them and help to run them off.
The Jets begin to dance down the street and snap their fingers until they are confronted by the Sharks on the basketball court and the two gangs begin to fight. The brawl is eventually broken up by a policeman.