From the publisher:
The Ds (Dick and Dorothea) meet the Swallows and Amazons during the winter beside the lake and they all become great friends: joining together in ice skating, learning semaphore signals, refashioning an igloo, and building an ice sled. But a misunderstanding could lead to disaster as Dick and Dorothea head off across the frozen lake to a spot they have named the "North Pole." And, Nancy, the Amazon leader, is stuck at home with mumps.
