The Thirteenth Mystery — Michael Dahl

Abracadabra, the founder of the Hocus Pocus Hotel has vanished! Charlie Hitchcock and Tyler Yu team up again to solve this mystery and find their friend. As the boys continue to search for clues, and as Annie Solo, a desk clerk at the hotel, helps them out, the last thing they expect happens. Tyler vanishes. But Charlie has reason to believe that a mysterious thirteenth floor exists in the old hotel...