Latin teacher Birger Sjögren at Ringsala boarding school threatens his possesive and chronically ill mother that he will get married. She gets a stroke and dies. Sjögren is affected by feelings of guilt, envy and hatred towards the surroundings. A series of mysterious fires have taken place around the school the last few months. One of the students has seen Sjögren setting fire to a barn. But can he convince the trusted biology teacher Nordmark, expert of the criminal mind?

Eva återvänder till Ringsala internatskola. Hon har under sommaren gift sig med Birger, en ny lärare på skolan. Rolf blir illa berörd. Han har alltid varit förälskad i Eva.