Spain, 1936. Three children - Ramallo, Tur and Francisca - witness one of their playmates perform a brutal stabbing and then commit suicide. Ten years later, the three friends meet again when Ramallo is sent to a sanatorium where Tur is already a patient and Francisca works as a nurse. Ramallo tries to escape, hoping to continue with a plan to defraud his partner Morell; but Tur has developed a strong sexual attraction to his old friend, and the resulting confusion leads to a terrible betrayal. Eventually, as events comes to a head, the incident they witnessed in their youth returns to haunt the young friends.