Marshy, rapidly eroding Holland Island in Maryland, USA, is a symbol of climate change. On the eve of WWI, things there change forever.

Marco knows the many secrets of Holland Island: the dune where he likes to play, hiding places in the trees, and above all, the birds–he can even mimic all their calls. He also knows the dangers: snakes hiding in the marshes, high winds, and the sea, which can often be cruel. That year, in 1917, two events turn Marco's wonderful little world upside down: his older brother Tom leaves for war in Europe, and a terrible storm threatens to engulf his island. But there's no way he's going to give up without a fight.