What happen at the beginning of west side story?

The story begins in the Upper West Side of Manhattan in the mid-1950s, where two street gangs, the Jets and the Sharks, engage in a turf war. The Jets, led by Riff, feel that their territory is being threatened by the Sharks, who are made up of Puerto Rican immigrants. Tony, the former leader of the Jets, tries to mediate the conflict between the two groups but finds it increasingly difficult to remain neutral as the violence escalates.

The action starts when the Jets are hanging out in a drug store. Action then shifts to a dance at the local gym, where Tony meets and falls in love with Anita, Bernardo's girlfriend. Tony and Anita's relationship is forbidden due to the rivalry between the Jets and the Sharks, and their love sets off a chain of events that leads to tragic consequences.