Goth Girl and the Ghost of a Mouse (Goth Girl #1) (2013 Costa Children's Book Award)

Recent winner of Costa Children's Book Award 2013.
 
Ada Goth is the only child of Lord Goth. The two live together in the enormous Ghastly-Gorm Hall. Lord Goth believes that children should be heard and not seen, so Ada has to wear large clumpy boots so that he can always hear her coming. This makes it hard for her to make friends and, if she's honest, she's rather lonely.

Then one day William and Emily Cabbage come to stay at the house, and together with a ghostly mouse called Ishmael they and Ada begin to unravel a dastardly plot that Maltravers, the mysterious indoor gamekeeper, is hatching. Ada and her friends must work together to foil Maltravers before it's too late!