Sapphire and Steel determine that Helen's bedroom is the location of a time break caused by the recitation of nursery rhymes. After narrowly avoiding a disaster, Steel boards up Helen's door to prevent the creatures inside from breaking loose. Rob begins to distrust the mysterious agents and sees a chance for escape when a policeman finally arrives in the morning. Sapphire is one step ahead of him, however, and traps the policeman in a time loop to prevent interference.

Lured by a vision of his father, Rob walks into a trap in the basement. A pool of light has taken him back in time to the 1700s when the house was first being built. Sapphire and Steel fear the worst when they discover that all three pools of light are there in the trap with Rob. However, Steel figures out that the creature that controls the pools of light has made a mistake and decides to gain the upper hand by using Helen as bait. Sapphire objects but follows through with the plan because it is their last chance to save Rob, bring back his parents, and return ...