Dot Watson just needs to be found. Every day, in the London Transport Lost Property Office, Dot Watson diligently catalogues the objects found on buses, tubes and trains. She's the custodian of hundreds of black umbrellas, a surprising number of shoes and one mid-century sofa. But it's not only the objects that are lost. Twelve years ago, Dot's life veered unexpectedly off course and she's never quite recovered. Like Dot, Mr Appleby has lost more than just a bag. His late wife's purse was inside and he's desperate to be reunited with it. Determined to help, Dot sets off to solve the mystery of the missing purse. Along the way she might just find something even more important - herself.