A Belgian girl, Carol, works as a manicurist at a London beauty salon. While having lunch, a good looking young man, Colin, spots her and makes a date for another evening. She shares a flat with her sister Helen. Her sister's married lover, Michael, brings out her dislike of men which she cannot explain to Colin. Michael takes Helen abroad for a holiday. Left alone in their flat, Carol's moments of catalepsy and hallucination increase and deepen into madness.