A successful FBI profiler, Illeana Scott (Jolie), is summoned to help out Canadian law enforcement in Montreal, to hunt down a serial killer who assumes the lives and identities (hence the title) of the people he kills as he travels across North America, which forces Illeana to adjust to working in a strange city with a police team with which she doesn't really fit in.

A scene was shot in which Angelina drives back to her house with the old pick-up and a branch from a tree falls and breaks the windshield. It took several takes to get the shot, and apparently destroyed the last remaining windshields for the pick-up available anywhere in North America at the time. The scene was not used.

Illeana:
Everything you saw I wanted you to see.

Errors in geography: When Scott is eating breakfast in the restaurant with the other detectives, a French-style police siren can be heard in the background. Canadian police sirens sound just like their American counterparts.

Music by U2
Lyrics by Bono and The Edge
Performed by U2
Courtesy of Island Records Ltd.
Under license from Universal Music Enterprises