On an ordinary evening, a mother and father sing nursery rhymes to their daughter Helen before bed. Their teenage son Robert becomes alarmed when all the clocks in the house stop working.

Sapphire and Steel determine that Helen's bedroom is the location of a time break caused by the recitation of nursery rhymes.

Sapphire and Steel investigate the upstairs hallway after Rob sees a pair of ghostly soldiers on the landing.

Steel's drastic measures to save Sapphire and trap the pool of light prove effective, if extremely dangerous.

The time break strengthens after a nursery rhyme hidden in a book becomes stuck in Helen's head.

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.