12-year-old Maeve Walshe's life is turned upside down when her family mysteriously inherits a beautiful but derelict castle in rural Ireland. The inheritance comes from her mother, who died when Maeve was born. Maeve longs to know her history, craving a sense of belonging that she's never felt. So when Maeve gets the chance to explore this new link to her past, she embraces it, accompanied by her ever-optimistic (and slightly annoying) younger half-sister Emma. But it turns out that Maeve's new home is full of secrets, ghosts and magic – and nothing is as it seems – including Maeve herself, who might just turn out to be a Lost Queen.