A bird lover out in nature serenely feeds a brood of swans that has ventured ashore. Then he douses the ground with gasoline and sets them on fire. Alarmed by the flames, a grandmother hiking nearby approaches the conflagration. The firebug sneaks up behind the woman and kills her with a blow to the head. Then he sets her alight.
At first, all Wallander knows is that there has been a fire in the forest, and a grandmother is missing. Of more immediate concern is a strange visit from Anna, a childhood friend of his grown daughter, Linda. Anna dropped in on the detective at his secluded home, talked about the trauma of her father’s suicide years before, and then vanished into the darkness.
As an increasingly desperate hunt for Anna unfolds, it becomes clear that she is mixed up with the arsonist. Fingerprints on a Bible buried with the grandmother’s charred remains identify him as an escapee from a prison for the criminally insane. His peculiar obsessions are the Book of Revelation and fire, and Anna is among the members of his tiny cult of scripture-quoting pyromaniacs.
Complicating the search is Wallander’s strained relationship with Linda, not helped by the fact that he once had an affair with Anna’s mother, Monika, a composer whose latest piece is a symphony of crying people. Little wonder that his romantic life is so depressing.
The arsonist strikes again when he sets fire to the biology lab of a former Christian high school that now teaches evolution. The coup de grace is that he also torches himself, dying—according to his suicide video—to atone for his sins.
Alarmingly, the other members of the cult start following suit, immolating themselves in places that they deem evil—for conducting stem cell research, performing gay marriages, or sanctioning ecumenical worship. “I am doing this in the name of him who was dead and who rose again,” each say in their farewell videos.
In an epiphany, Wallander guesses that the final statement is not the usual New Testament reference, but one to the cult’s flesh-and-blood leader, who is not dead, although everyone thinks he is. Could it be Anna’s father, Erik, a known religious fanatic before his presumed suicide?
A visit to Monika confirms that she held a sham burial for Erik after he abandoned the family years earlier. She told the young Anna that he had killed himself. Now he has apparently returned from the dead, reunited with his dumbfounded daughter, and decided on violent retribution against a sinful society.
Briefly called away to thwart a suicide mission against an abortion clinic, presumably by Anna, Wallander gets a frantic call from Monika: Anna and Erik are at her house! When Wallander arrives, Erik is sitting at a table with his daughter and estranged wife. He has doused the room with gasoline and is holding a cigarette lighter. Coolly, Wallander discusses the moral implications of the situation. He can’t convince Erik, but he does persuade Anna, who grabs a knife and jabs her father’s hand, causing him to drop the lighter. He is then wrestled into custody.
The episode ends with Wallander and Linda at a maternity clinic. She is pregnant and in a few months time he will be a grandfather. But can such a blessed event let a ray of happiness into this man’s tortured soul?