' You know what it's like. Dark at teatime & sleeping indoors: nothing ever happens in the winter holidays.'" Or so Nancy thinks. Then the lake ices over completely & the Swallows & Amazons along with Dick & Dorothea -- 'the D's' -- plan a race to find the North Pole. How will they reach it if they can't sail? By sledges of course! But when a blizzard blows up & there is a mix up about signals the D's disappear into the Arctic night. Disaster looms. Can the Swallows & Amazons save their friends?"