Fredrik Welin is a seventy-year-old retired doctor. Years ago he retreated to the Swedish archipelago, where he lives alone on an island. He swims in the sea every day, cutting a hole in the ice if necessary. He lives a quiet life. Until he wakes up one night to find his house on fire.

Fredrik escapes just in time, wearing two left-footed wellies, as neighbouring islanders arrive to help douse the flames. All that remains in the morning is a stinking ruin and evidence of arson. The house that has been in his family for generations and all his worldly belongings are gone. He cannot think who would do such a thing, or why. Without a suspect, the police begin to think he started the fire himself.