Allie Jones (Bridget Fonda) kicks her two-timing boyfriend Sam (Steven Weber) out of their apartment and in turn, seeks a roommate to help cover the cost of the rent and to make her boyfriend see that she can live without him.
Hedy Carlson shows up at the door and they get along famously at first.
Hedy is unemployed and rather pathetic, but she helps Allie through the rough patch without Sam and the two spend all their free time together and become close.
Hedy even brings an adorable puppy home for them to share.
What Allie doesn't know is that Hedy has been erasing phone calls from Sam, who wants them to get back together. About the same time, the puppy takes a tumble out the (rather high) apartment window. It does not end well.
Furthermore, Hedy starts dressing more like Allie, and when Hedy finds out Allie and Sam have reconciled, she begins to copy Allie's wardrobe almost stitch per stitch, and even goes as far as getting a haircut and dye job that matches Allie's firecrotch red exactly. They look so similar it's eerie....and completely disturbing to Allie, who confides her misgivings to her neighbor Graham, who is a good friend. He advises her to send Hedy packing.
Allie also searches through Hedy's room and discovers that some bad things happened in her past (a dead twin sister and alot of depression) that prove it would be prudent to get her out of the apartment as soon as possible.
As if all this isn't enough, Hedy (which actually isn't even her real name) brutally attacks Allie's neighbor, nearly killing him. Next she seduces Sam, pretending to be Allie and sneaking into his bed late at night to give him oral sex. Sam doesn't notice at first (naturally!), but after realizing it is Hedy he finds his senses and pushes her away. Rejected and pissed, Hedy stabs Sam in the eye with her stiletto, killing him. Nice one.
Soon after, she holds Allie hostage (to what end, I ask?) in Graham's apartment. When someone comes looking for Allie, Hedy shoots the visitor dead.
Eventually there is a big, extended showdown in which Hedy meets the bad end of a screwdriver.
But man, that scene in the movie where Hedy comes walking down the salon steps (with Allie watching) looking exactly like Allie... scary as hell.
Buy it here.