When a young woman dies peacefully in her sleep, her husband sits distraught at her side. Returning to his job at the Finland CID he finds that a murder inquiry is just beginning. A woman has been smothered while she slept and, as the case unfolds, others will be found having met death in the same eerily tranquil way.

The young policeman, stricken with his grief, starts to feel an affinity with this humane killer. Meanwhile the murderer's dysfunctional relationship with his own cracked personality spawns behaviour which grows increasingly intense.