Geteiltes Leid (2000)

One night, a man named Christian receives a phone call from a stranger. The man on the other end of the line calls himself Ralph and threatens to kill himself on the spot if Christian hangs up. Confused, Christian decides not to hang up. During the conversation, he slowly elicits some information from Ralph: he learns that Ralph accidentally killed a woman with a razor blade during sex and now doesn't know what to do. Slowly, Christian figures out who this woman is...