Derry. 1689. The city's inhabitants resist all attempts by the King James's men to storm their gates. Outside, the soldiers reckon the only effective weapon they have left is to starve them out...

Luna is the only one to mourn her grandfather's death - the rest of her family couldn't be happier to see the back of the old miser. Then her family start to disappear... Luna's sure it's her grandfather haunting them from beyond the grave but Skeleton Keys is convinced it's the work of a mysterious unimaginary.

When troublesome unimaginary Wordy Gerdy uses her ghostly pen to write Skeleton Keys' precious keys out of existence, he has to follow her into the past to restore them. But her pen is now in the hands of notorious thief Gap-tooth Jack...