Olga Brenner is a weathered housewife who lives in a disheveled seaside cottage with her abusive husband Mart, their mentally-ill son Tobey, and Mart’s infirm mother. The family lives in poverty, ostracized from the nearby village due to Mart’s erratic antisocial behavior. Tobey spends his days capturing butterflies with which he adorns the walls of the cottage. On a foggy day, when Mart is not home and Tobey is out on the beach seeking out butterflies, Olga is startled by a scream coming from the hills near their residence. Following the incident, Mart’s mother sporadically cries out the phrase “blood on his hands,” among other foreboding messages, which contributes to Olga’s feeling of unease. Eventually, Tobey returns, tracking soaking wet boots through the cottage, but cannot recall hearing the scream, although he offhandedly mentions seeing his father during his day. Olga worries that Mart will punish Tobey for soaking his boots. Presently, Mart returns and addresses Olga with inexplicable friendliness. He himself tracks mud through the cottage, but quickly replaces his boots with those that Tobey was wearing.  There is a knock at their door, and a group of men, including the village sheriff, gather in the house and announce the discovery of a body upon the hills near the cottage. As the group interrogates the whereabouts of Mart and Tobey that afternoon, Olga becomes defensive but suspects that her husband’s suspicious behavior may be related to the discovery of the body. When the sheriff questions the couple about the muddy footprints, Mart lies and says they are Tobey’s. As evidence mounts against her son, Olga proclaims Tobey’s innocence and tries to stop the group from arresting him, but to no avail. Tobey is led out of the house, and Mart quickly drops his amicable veneer. He produces a bag of coins stolen from the man he killed and begins assaulting Olga. Mart’s mother, who has continued with her sporadic outcries through the course of events, sees her son thrashing Olga and runs out of the house screaming, which calls the attention of the men heading back to the village with Tobey. As the men begin to return, Olga, battered but still conscious, triumphantly jeers that the stolen money will implicate Mart in his crime.