Sylvia, alone and pregnant in the deserted Manhattan high-rise she shares with her husband Noah, awaits her husband and a dinner guest, Mr. Swanson. In spite of the blackout, Swanson arrives and engages Sylvia in a disturbing conversation. But when Noah gets home, Swanson vanishes. As the night continues, sights and sounds become even stranger and more ominous. Are they Sylvia’s hallucinations, or is the danger real?