The Bookstore Burglar (Penguin Young Readers, Level 3)

Someone stole the key to the Black Cat Bookstore! Lucky for the store's owner, Mr. Brown, his clever cat, Cobweb, is on the case. Cobweb has a plan to scare the burglar away, and the ghost who lives in the bookstore is happy to help. There's only one problem-the burglar doesn't believe in ghosts. But maybe he'll change his mind once he meets the special ghost who lives in the Black Cat Bookstore.