In the thirteenth book of the Capital Mysteries—an early chapter book mystery series featuring fun facts and famous sites from Washington, D.C.— KC and Marshall have tickets for the express train out of Union Station. It even has a VIP car at the back for the vice president, the kids, and the secret service agents to travel in. But when KC and Marshall sneak away from the secret service agents to go exploring, someone tampers with the train! And that someone is searching – car by car – for KC and Marshall. There’s nowhere to run!