Jakob Aasen asks his old friend, private investigator Varg Veum, to spy on his wife Rebecca, whom he suspects of infidelity. Against his better judgment, Varg accepts the job, and in an ironic twist, he and Rebecca rekindle their former love. Meanwhile, a serial killer is targeting members of Jacob's band and their families...
A vocalist of a rock band asks his old friend, a private investigator, to spy on his wife whom he suspects of infidelity. The private dick accepts his request and starts tailing his wife, who catches him doing it. Based on the dick and the wife's dialog, they had actually cheated on her husband a long time ago, when the couple wasn't married yet.
While they are talking, the wife makes her move and kisses the investigator. The dick is reluctant, but hey, it's a free ready-to-cheat wife available for his taking, so he fucks her. They do it on the couch, in a sitting position at one point, with her bouncing on his lap. These all happen in the first 20 minutes of the movie.