In 1987 Poland, a police officer investigating mysterious disappearances infiltrates a remote monastery and discovers a dark truth about its clergy.

In a monastery cut off from the world, the monks run a clinic for the possessed. One day, a young policeman Marek comes to the convent. Posing as a clergyman, he penetrates monastic life and tries to explain the recent, mysterious disappearance of several tormented inmates. It turns out, however, that there is no way out of the monastery.