Sapphire & Steel: Assignment I: Escape through a Crack in Time (2)

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.