In the aftermath of World War One, everyone is trying to rebuild their lives. If Ben is to avoid being sent back to the orphanage, he needs to find his brother Sam, wounded in action and is now missing. Lotti's horrible aunt and uncle want to send her away to boarding-school (when she has just so successfully managed to get expelled from her last one!) And Clara, their young teacher, is waiting for news of her missing fiancï¿½.
Just as they think they've found their feet in the new order, disaster strikes, and Lotti and Ben must get away. And so they hatch a plan - to cross the Channel on Ben's narrowboat, to find Sam and to look for Lotti's French family house, a place which she has only visited once but never forgotten.
Buffeted by storms, chased by the police, Lotti, Ben, Clara and a growing number of dogs (one stolen) pursue their watery course, on the search for lost loved ones and a place to call home.