A happy family lives in an 18th-century house filled with clocks and antiques. One night, a nursery rhyme ("Ring a Ring o' Roses") read aloud to Helen, the little girl, triggers a time fracture that takes away her parents. As Rob, Helen's older brother, tries to understand what has happened, two mysterious strangers appear, promising to fix things. Sapphire and Steel eventually gain Rob's trust and work out a solution to the problem. Lead also arrives to provide assistance.