When a mysterious stranger claims to own Becca's beloved zorse, Zed, something seems suspicious. Besides, if this person is Zed's real owner, the Curious Cat Spy Club fears he might be responsible for abusing Zed in the past. Kelsey, Becca, and Leo are determined to uncover the truth before they have to give Zed away. But when a daring rescue attempt puts Kelsey in danger, does the CCSC have enough spy skills to save her or are they in over their heads?