Mo's older brother has to go away for work, but just like the swallows, he'll return to him when the summer comes. Bibi and Mo love to watch the first swallows arriving home to their lake in the summer. But soon, just like the swallows, Bibi has to go north for work. He tells Mo to think of him flying with the birds, and just like the swallows, when summer comes again, he will journey across the cities, oceans, grasslands and jungle, and over the tops of the mountains back to Mo.