Four Degrees of Jonas Rydell

A scientific experiment gone wrong has produced three copies of Jonas Rydell, a young man residing in a wintry Stockholm suburb. Each copy thinks he is Jonas, sharing his instincts. Unless Jonas manages to kill them all, he will age twice as fast and be prone to twice the amount of diseases for each copy still out there. As Jonas enters his girlfriend's apartment, he realizes that someone else entered just before him...