Trixie Belden's best friend Jim ran away before anyone could tell him that he is the heir to a major fortune. Secrets shift into high gear when Trixie and her friends set off on a road trip to find Jim--and uncover another mystery along the way!

When Trixie Belden's friend Jim runs away, she and her neighbor Honey jump in an RV and hit the road. Someone has to tell Jim he inherited a fortune--but he needs to be around to claim it!

Unfortunately, Trixie and Honey's troubles are only beginning. The girls learn there's been a string of break-ins to campervans, making travel more dangerous than ever. What's worse, a young girl named Joeanne has disappeared into the woods, leaving her family and their shiny red trailer behind. Trixie and Honey worry that Joeanne could be in danger--and the fear only grows as the car bandits get more bold. The race is on to find Jim and Joeanne and untangle the mystery of the road trip thieves before the burglars hit the brakes on Trixie's adventure once and for all.