When Carol, a shy young Belgian, is left alone for a few days in the Kensington flat she shares with her sister, her grasp on reality begins to crumble. She begins to withdraw into a reclusive existence where innocuous everyday realities are distorted by deep-seated anxieties.

Motored by a spiralling, serrated edge-of-your-seat tension, Polanski’s nervous, profound psychological horror leaves leading lady Catherine Deneuve in distress, cornered and enclosed in his innovative mise en scène.