The Travel Agency is in the business of time travel, and time travel hasn't worked out the way its creators had hoped it would. Finding themselves unable to change history, except in very small ways, the Agency does what any group of scientists and multi-billionaire investors do when confronted with an initially promising product that isn't living up to the serious purpose for which it was invented: they turn it into a form of entertainment. Time travel becomes time travel tourism, and teenagers from the past are rescued (or "recruited," as the Agency calls it) from various life-threatening situations, and pressed into service as travel agents. Their job is to escort rich, hard-to-please tourists to the past and back again, enduring the inevitable comments that the past isn't nearly as nice as they thought it would be. Sixteen-year-old Rosina, who was recruited from Victorian England, finds her work as a travel agent is beginning to get her down. She's been on the job for more than a century, and she doesn't know how much longer she can stand it. When her boyfriend, the intriguing but unreliable Ned York, reveals his surprising true identity, and asks her to join her on a dangerous mission, she agrees. Unfortunately for Rosina and Ned, their mission may land them in the Agency's secret prison, a place called Time Out, for a very, very long time.