Sapphire and Steel step in to aid two children whose parents are lost in time when they disappear from their remote, coastal home whilst reading nursery rhymes to their daughter.

Sapphire and Steel determine that Helen's bedroom is the location of a time break caused by the recitation of nursery rhymes, and they must try to prevent unknown entities from escaping.

Sapphire and Steel investigate the upstairs hallway after Rob sees a pair of ghostly soldiers on the landing, but a frightening, unseen power soon begins to menace Sapphire.

Steel takes drastic measures to save Sapphire and trap the pool of light by attempting to freeze it, while the duo then hurry to get rid of other house objects before they also become a refuge for the entities.

Lead helps Sapphire and Steel in their fight to overcome the forces of evil in the house as the time break strengthens after a nursery rhyme hidden in a book becomes stuck in Helen's head.

Rob is trapped in the cellar after being lured by a figure he takes to be his father, while Sapphire and Steel fear the worst when they discover that all three pools of light are there with him.