The final book in The Trapdoor Mysteries, a series about Tally, a code-breaking, animal-loving girl and her best friend, a squirrel named Squill, who solve mysteries with the help of a secret library... Tally was once a servant girl at Mollett Manor - as well as the Secret Keeper of the magical library hidden underneath the manor's grounds. Along with Squill the squirrel, she used the enchanted books in the library to solve crimes...