Roger Winstanley (Menzies), who for 15 years has been haunted by a recurring nightly nightmare: he is invited to spend the night in an friend's house, and is assigned a room in the tower – a space that fills him with dread though he isn't sure why. In his waking life, Roger is invited to his friend's country house, which bares a striking resemblance to the house of his dreams. Nightmare and reality collide when Roger is invited to stay the night in the room in the tower.