Act 1: The reception hall of a small boarding house, noon
Martha and her Mother, together with a taciturn Old Man, run a guest-house in which they murder rich solitary travellers. Martha wants to get enough money to go and live by the sea. Mother is exhausted by killing.
Jan returns to the house he left 20 years ago. He has heard his father was dead and has returned with money for his mother. He expected to be welcomed as the prodigal son, but his mother does not recognise him. His wife Maria says a normal person would simply introduce himself, but Jan intends to observe his family from the outside and find what they really need to make them happy. Maria reluctantly agrees to leave him there for one night.
Jan registers under a false name. Martha is cold and refuses to answer personal questions. Mother fails to respond when Jan hints at his purpose in coming and asks if she had a son, but she begs Martha not to kill him.
Act 2: The bedroom, evening
Martha warms slightly towards Jan, but when he becomes interested in her she rejects the shared moment and determines to kill him. She brings him a drugged cup of tea. Mother tries to retrieve the tea but is too late. Jan tries to express his feelings to her, but Mother replies impersonally. When Jan falls asleep, Martha takes his money and they prepare to throw him in the river.
Act 3: The reception hall, morning
In the morning, Martha is happy but Mother just feels tired. The Old Man finds Jan's dropped passport and they realise without emotion what they have done. Mother decides to drown herself, disregarding Martha's protests. Martha is left alone with her anger.
Maria arrives, looking for her husband. Martha first says he has left, but then admits they drugged and drowned him for his money, saying it was “a slight misunderstanding” that led her to kill her own brother. Maria is distraught. Martha coldly compares it to her own loss of her mother. Then realising she is alone she decides to kill herself. She tells Maria to pray God turns her to stone or kill herself too, then leaves the house. Maria prays for mercy and the Old Man appears. Maria asks for help but he bluntly refuses.
