Chinatown ending explained

What happens

Jake leads Evelyn and Katherine to Chinatown to escape Noah Cross, but police are waiting. Evelyn is shot dead, and Cross takes Katherine, his own daughter and granddaughter. The man behind the crimes wins, and Jake can only watch.

The last line

"Forget it, Jake, it's Chinatown."

What it says

Jake understands everything and still cannot stop it. The film argues that knowing a corrupt system is not the same as beating it, and that power protects itself. Polanski chose this bleak ending because the story's moral logic demanded it.