'Well,' said Nancy, 'You know what it's like. Dark at teatime and sleeping indoors: nothing ever happens in the winter holidays.' Nothing - except a polar expedition, full of mountain rescues, blizzards, igloos, ice sailing and heroic work amidst the frozen wastes. For Dick and Dorothea, newcomers to the lake, meeting up with the Swallows and Amazons sweeps them into a wild adventure where they must prove their worth to the team.