The action takes place at the summerhouse of the Karlberg family in the archipelago of Stockholm. The daughter, Susanne, 17, has introduced. Martin, also 17, to her parents Ingeborg and Jan. Ingeborg is tempted to seduce the boy when Gertrud, an ex-pupil of Jan's arrives, a ghost from his past. She assumes a malevolent role in the mix. The family has a skeleton in their cupboard; a brain-damaged son who lives in an institution. As the drama unfolds, Gertrud plays the part of intruder, temptress and catalyst. As the past is exposed, passion revealed the atmosphere is cleansed and Gertrud leaves defeated.