House of 9

"Nine strangers. One house. Only one will get out..."

—Poster tagline

A 2004 film originally released in the Cannes Film Festival before being released in the US the next year, House of 9 is a thriller film directed by Steven R. Monroe.

The film's premise has nine people kidnapped and shipped to a mansion with boarded doors and windows: Father Duffy, the priest; Jay, the detective; Lea, the dancer; Claire, the tennis player; Francis, the musician; Cynthia, Francis' wife; Al B, the rapper; Shona, the drug addict; and Max, the designer.

When they all awaken and meet up in the same room, a voice from a speaker introduces himself as The Watcher. He informs them that they're trapped in the mansion with 75 surveillance cameras and will not be released unless only one person is alive. The remaining player will then walk out of the house and be rewarded five million dollars. Realizing that there is no way to bust through the mansion, they decide to keep their wits and get through this game. However, as time passes, the players find themselves succumbing to greed, fear, and mistrust, causing the mansion to be transformed into a warzone, where only one will win.

Tropes used in House of 9 include:

Decoy Protagonist: Boy, I bet you thought Ray, the police officer and single father, would be making it through with Lea, right? Nope!
Downer Ending: Lea is allowed to walk out with her five million in a bag. However, when she goes through, she finds herself in an identical foyer with four other people that have the same bags with them, scared and on the verge of crying. She then realizes that she'll have to play a new game.
- A different ending has Lea walking up in her own apartment, finding the five million and a tape nearby. The tape plays, the Watcher telling her that along with her prize money, she earned the rights to join an exclusive survival club. As the tape ends, it shows nine new people in the same bedroom that the original nine were placed. It then dawns on Lea that she's The Watcher of the new nine.
Driven to Suicide: Al B. It's left ambiguous whether he actually did it out of guilt for having killed Ray, or if he was killed.
Electrified Bathtub: Subverted. Francis attempts to kill Lea by ripping a light fixation while Lea washes her hands and drop it into the sink. Lea is shocked and knocked out, but awakens later.
Final Player: Lea
In the Back: Francis stabs Father Duffy in the back before stealing the gun from his hands.
Sanity Slippage: Most of the players go through this as time goes on, especially Francis.