After a slight misunderstanding involving a horrible governess, gravy, and a jar of tadpoles, Tobias and Charlotte Eggers find themselves abandoned by their father at the gates of a creepy reform school. Sinister mysteries are afoot at Witherwood, where the grounds are patrolled by vicious creatures after dark and kids stay locked in their rooms. Charlotte and Tobias soon realize that they are in terrible danger - especially because the head of Witherwood has perfected the art of mind control. If only their amnesiac father would recover and remember that he has two missing children. If only Tobias and Charlotte could solve the dark mystery and free the kids at Witherwood - and ultimately save themselves.