The story: An American student in Paris (Matthew) befriends a set of fraternal twins (Isabelle and Theo), bonding with them over their shared love of all things cinematic. Matthew, both unsettled and intrigued by the twins' all-but-incestuous relationship (they kiss, sleep together naked, and play humiliating sexual games) and completely infatuated with the two of them, comes to stay with them while their parents are away and lets himself get sucked into their strange little world.
I absolutely adore this movie. The twins' relationship is fascinating; as a Wincester especially, I love the idea of siblings who are in love with each other but refuse to take that final step and become lovers. I love the idea of them finding a third to act as a sexual proxy, someone pretty and eager and manipulatable. And I love how torn Matthew is between taking that role, trying to be the third piece of their twisted puzzle, and wanting to live in the real world.
Also: there's an almost unbearably hot sex scene (the film's rated NC-17, y'all) where Theo holds Matthew down as Isabelle strips him. That scene alone makes the movie more than worth watching. (If only more het porn would like this, I wouldn't be watching exclusively m/m porn vids.)
Nnngggghhh, watch it!