While in a hospital, Liz Powell, an over-worked professional dancer, has a strange, recurring nightmare. In this nightmare Liz experiences a false awakening - a vivid dream about awakening from sleep - in which she sees herself awakening suddenly to the loud sound of a ticking clock. As she reaches for a drinking glass full of water the ticking sound becomes so loud that it drowns out all other sounds. Her hand shakes so violently that she loses her grip on the glass, which drops to the floor and shatters. Suddenly the ticking sound stops. Liz then hears strange footsteps outside her door. As she exits her room she sees an elevator, and notices that the nurse is on the elevator. The Nurse's face is hidden in the shadows, but Liz sees her clearly as the elevator door closes. Liz sees the el