The Moss family needs to get their pianola out of hock in time for the street party, so headstrong young Ruby must go out and earn money. But her new job as a corsetiere, together with competing for a place in the Olympic swimming team, is taking its toll. Brother Billy is the only one who can help but he is suffering his own nightmare due to his traumatic war experiences. The day of Ruby's swimming race arrives and Billy's fear of water reaches crisis point.