Think back over the ending. A jail cell holds the most famous act in America, and the man who opens it is the hero from the radio. Two futures are laid on the table: one paved with movie money, one paved with ice. A house painter looks at twelve birds who have given him fame, fortune, and the best year of his life — and gives them back the cold. Then a ship’s whistle blows, a family waves from the dock, and the dreamer of Stillwater sails north into the life he always read about.

At the top and bottom of the globe lie two frozen worlds that people constantly confuse — and that could hardly be more different. The Arctic, in the north, is an ocean of frozen and drifting sea ice surrounded by continents; the Antarctic, in the south, is the reverse: a true continent of rock buried under mile-thick ice and surrounded by ocean. Their famous animals never meet. Polar bears roam only the north, while penguins swim only in southern waters — because for a cold-water bird, the warm seas around the equator form an impassable barrier of heat. In the 1930s, curious scientists actually tested nature’s arrangement: small groups of penguins were released on islands off Norway, in the far north, to see if a colony might take hold. The experiment failed within a few years, and no wild penguin waddles the Arctic today. Geography, it turns out, is not easily rearranged. The two poles remain what they have always been: twin kingdoms of ice, each with its own crown — one wearing the bear, the other the bird in the black-and-white suit.

No right or wrong — tell someone nearby what happened in this part. Can’t find anyone? Tell yourself out loud. The moment you teach it, you truly understand it.