Twelve-year-old Lizzie Durango lives in a zoo, spending her days taking note of the animals' behaviors, then she meets runaway Tyler Briggs and together they investigate the wolves who are suddenly dying.

Detectives' Row is full of talented investigators, but Toby Montrose isn't one of them. He's only an assistant at his uncle's detective agency, and he's not sure he's even very good at that. Toby's friend Ivy is the best sleuth around -- or at least she thinks so. They both see their chance to prove themselves when the famed Hugh Abernathy announces a contest to choose the World's Greatest Detective. But when what was supposed to be a game turns into...