It's time for the annual pet fair and the twins have been hard at work teaching their dog, Max, some new tricks. But on their way to the fairgrounds, they're offered not one, but two intriguing cases. Pets from the pet show have gone missing and their guardians are blaming each other for the disappearances. Meanwhile, Lark and Connor's frenemy, Sophie, thinks her house might be haunted and refuses to go inside. The twins split up to solve the mysteries, but can they find the vanished pets and the source of the spooky noises before the show has to start?