It is the day of young Hugh Anthony's birthday picnic. A procession of landaus and victorias, plus one motor car, are bound for the Blue Hills and Hugh's picnic.
Whatever the reason, each vehicle gets mysteriously lost on its way to the Blue Hills, and by the time the travelers meet again over tea and iced birthday cake, they have had such adventures. Adventures such that none of them is the same person. They are wiser, nicer and much happier.