Mrs. Babbage has lost her late husband's pocket watch. Mr. Binton, one of the residents at her retirement home, was about to fix it when he suddenly died of a heart attack. The watch disappeared in the commotion. The Home School Detectives are called on to investigate.

Meanwhile, to complicate matters, Clarice pushes her way into the case, offering Julie, Rebecca and Emily help they really don't want from their annoying friend.

The girls become even more concerned when Mrs. Babbage is mysteriously found unconscious. And they begin to think that Mr. Benton's death is suspicious too. Are the two events connected? And is there a bigger puzzle underneath waiting to be solved? Join the Home School Detectives as they unravel their eighth mystery.