You have to stop this2011
(You have to stop this (Secret series #5))
by Pseudonymous Bosch
When a mummy disappears from the local history museum while Cass and her friends Max-Ernest and Yo-Yoji are there, they try to solve the case in order to clear their names and, they hope, discover the Secret they have been seeking.
— from OpenLibrary
1 edition at OpenLibrary