In September 1913, Mieczysaw, a student suffering from tuberculosis, arrives at Wilhelm Opitzs Guesthouse for Gentlemen, a health resort in what is now western Poland. Every day, its residents gather in the dining room to imbibe the hallucinogenic local liqueur, to obsess over money and status.

Meanwhile, disturbing things are beginning to happen in the guesthouse and its surroundings. As stories of shocking events in the surrounding highlands reach the men, a sense of dread builds. Someone–or something–seems to be watching them and attempting to infiltrate their world. Little does Mieczysaw realize, as he attempts to unravel both the truths within himself and the mystery of the sinister forces beyond, that they have already chosen their next target.