It starts as a seed that Big Bear and Little Bear find in their food and plant just to find out what it is, and it grows so big that the two bears cut out some windows and move in with their stove, beds, and honey jars. When it comes off its stalk and blows into the sea they simply become ""sea bears"" and get out their fishing rods, and when the fire they build in winter fills it with warm air, it rises like a balloon and sails away--and ""Now we're air bears, off to see the world."" In contrast to the oversized pumpkin, Lennart's fancy is slight, but uninflated (though her observation of the colors of the two bears' possessions--""Big bear had a gold one and Little Bear's was silver""--is a child-level touch that wears out when we're told the same thing about their umbrellas, trowels, boots, fishing rods, and axes). Overall, a satisfactory arrangement of that trusty combination, domestic security and a spirit of why not.