The Gold Mystery #8 (The Whodunit Detective Agency)

When a valuable shipment of gold disappears from the vault at the Pleasant Valley bank, Jerry and Maya are called in to help crack the case.  There are no witnesses and there's nothing on the security cameras, so it feels like the gold vanished into thin air.  But once again, with their super sleuthing skills, the young detectives help the police chief get to the bottom of the mind-boggling mystery.