Nancy Drew, Girl Detective Books

After Stealing a million in investment cash, a desperate robber commandeers a hot air balloon at the local exposition, only to be lost in a raging storm. The balloon was tracked to a high mountain area before going down. When Police Chief McGinnis refuses to take Nancy on the recovery effort, she and the girls stowaway with the investment bankers, also climbing the mountain, in an effort to recover their funds. Unfortunately, once the balloon is found, they learn that they’ve hung out with the wrong group - the bankers were in on it with the robbers!