Minty's summer begins with a tragedy that puts her mother in hospital. This sets off a chain of events that sends her back in time and into a struggle against dark forces.

As she explores the past, Minty meets the mysterious hooded child from the house and witnesses the miserable life that Tom leads as a kitchen boy in his Victorian household.

Minty desperately tries to warn the children of the arrival of a ghost hunter in the village. The evil Miss Raven spells trouble for them all.

Miss Raven, the sinister ghost hunter, comes to stay at Aunt Marys. As Minty explores the mysteries of the Moondial, Sarah's terrible secret is revealed.

In the past Minty discovers that Sarah's governess, Miss Vole, bears a striking resemblance to Miss Raven. Whilst there she and Tom witness the cruelties that Sarah has to endure.

Minty and Sarah set out to rescue Sarah from Miss Vole. However it is Halloween and the forces of darkness are strong in all of the times touched by the Moondial.