When Ethan and Ella learn that their mother has accepted the position of travel writer for The Brookeston Times, they are not happy. Move away from Brookeston? Say good-bye to all their friends? What could be worse? Their mom and dad promise them that this will be a great experience, but that doesn’t make the kids feel any better.

The day before they are set to leave, their beloved Grandpa Harry stops by. As a gift, he gives Ella a pretty journal since he knows she loves to write and Ethan a gold coin that Ethan decides he will always keep in his pocket. But the morning of their departure, Ethan realizes he's lost the coin! Together, he and Ella must retrace their steps from the day before. Will they solve the mystery of the missing coin before it’s time to head to the airport?