Chinatown (1974)

In 1930s Los Angeles, a private detective named Jake Gittes is hired to spy on Hollis Mulwray, chief engineer for the Los Angeles Department of Water and Power. When Gittes discovers that he was set up and Mulwray ends up dead, he starts investigating the corruption and deceit behind the city's water supply. As Gittes uncovers the truth, he realizes the extent of the conspiracy and must confront the powerful figures involved. Ultimately, he must make a difficult choice that reflects the dark and twisted nature of Chinatown.