Martin has a hard time coping with his younger brother Thomas being the favorite son of the family. Martin and Thomas both live with their father, a forest warden, in a house in the middle of the pines in the Lande region. Their father only has eyes for Thomas. One spring morning, as per usual, the two brothers set out go fishing together. On the lake, Martin murders his brother, as he intended to do, and sinks him in the river beneath a sack of rocks. After this drama and, deep in a lie, the teenager naively thinks he will win back his father's heart.
Freely inspired by the biblical story of Cain and Abel.