Karen has come to stay with Nicholas and his mentally distrubed sister, Hester. Nicholas and Karen's father were partners until Karen's father suddenly vanished. Hester tells Karen the door in the room concealed by a drape has not been opened for seven years. Hester claims a key on a red ribbon in Nicholas's possession opens the door. And that there is a corpse hidden there! Remembering it was seven years ago that her father disappeared, Karen's suspicion increases and the red key becomes a symbol of fear and mistrust.