Jack Nicholson starred in both.
"Chinatown" while a specific place, is also indicative of the unknown where motives/behaviors are never clearly understood and the hope is you do no harm by doing "as little as possible."
Jack Gittes ( Nicholson) is a private detective who used to be in the L.A. Police department where his beat was Chinatown. In his attempt to help a Chinese girl, he ends up inadvertently getting her killed because he does not understand "Chinatown" and he forgot the one rule, "Do as little as possible."
He leaves LAPD and becomes a high profile private detective. He's asked to investigate an adultery case which ends up being a murder case and deepens into a swamp of unseen conflicts and family tragedies
At the end of the movie in Jake's attempt to help the woman who's husband was killed by her own father who also raped her and got her pregnant with her daughter, Kathryn, he ends up getting her shot and killed by the LAPD while the wealthy but evil grandfather/father ends up with the daughter, the prize.
In the final scene as Jake is starring at the dead woman while the car horn continues to blare he mutters softly -
"As little as possible."
Lt Escobar yells, "What's that? what's that?
You wanna do your partner a big favor? Take him home, take him home. Just get him the hell out of here. Go home Jake, go home. I'm doing you a favor."
Jake is finally turned away from the scene and his associate utters one of the saddest most poignant lines in movie history.
"Come on Jake," (Jakes turns back for a moment) "Forget it Jake, it's Chinatown."
THE TWO JAKES:
The second movie's time frame is a few years later. There is a troubled mystery woman who's infidelity gets her husband's business partner killed with whom she's been having the affair. The young woman turns out to be Kathryn, the young girl who's mother and step-father were killed by her grandfather - who was actually her biological father.
Jake becomes involved in the case, then the husband of Kathryn, dying of cancer, blows himself up to settle some debts and insure Kathryn's safety.
In the final scene; Kathryn is talking to Jake in his office.
KATHRYN: Does it ever go away?JAKE: What’s that?
KATHRYN: (The) Past.JAKE: Well, I think you have to work real hard on that.
KATHRYN: I can’t do it alone.
JAKE: I don’t suppose you’ll have to.
( KATHRYN attempts to kiss Jake who backs away)
JAKE: That’s wrong.
KATHRYN: Don’t be too sure.
JAKE: That’s your problem kid, you don’t know who you’re kidding.
KATHRYN (getting ready to leave): You take too good a care of me Mr. Giddes
JAKE: Tough habit to break
KATHRYN: I’ll think of you from time to time.
( KATHRYN leaves the office and heads down the stairs – there's a pause – then Jake burst out of the office and yells)
(quietly) it never goes away."
Both movies had brilliant but ultimately sad endings. There was no redemption and no reason to think anybody lived happily ever after. But if you like your movies "straight up," you might give them a shot. [ NOT sure of the ratings; but both should be "R" for violence and some sexuality. The scenery, cars and shots of SoCal were gorgeous. ]