An abandoned castle, a valley infested by evil spirits, and a cursed family ... an exciting new adventure for the River Hawks!

Twelve-year-old Izzy is excited to be spending the summer holidays with her Italian grandmother. She eagerly listens to spine-tingling tales of the evil spirits that once infested Val De Monio, in awe of the Guardians who did battle with them. But when Gran tells her about a Mazzapeghoul, a wicked demon, still inhabiting Malasorte Castle, Izzy starts to doubt whether her stories are true.

When her new-found Italian friends suggest spending a night in Malasorte Castle to prove it isn't haunted, she jumps at the chance to join them. But things start going bump in the night, and they begin to wonder if the Mazzapeghoul is more than just a local myth.

Why did the last members of the family flee the castle in 1932, leaving it empty and desolate? Can Izzy and her friends solve the puzzle and break the curse on the castle before it's too late?