Addy and Prue Fairweather live with their widowed mother Nell, in a flat above her shop. Addy is plain and always in trouble whereas Prue is as angelic as her looks imply. To make matters worse, Nell makes no secret of her preference for the younger girl, increasing Addy's jealousy. On the other side of the coin, Giles Frobisher and his twin sister, Gillian, live in a crumbling mansion in Devon. The family have lost most of their money in the Depression, so Giles joins the Fleet Air Arm. He meets the Fairweather girls briefly but they lose touch. When they meet again the girls are no longer children and Giles realises he is falling in love.