Seven-year old Anne-Kathrin and her brothers, the five-year old Henrik and the four-year old Erik live on a 17-hectare holm in the North-German wadden sea. There are no crossroads, no high-rise buildings, no underground railway, no cinema and no zoo. But there are adventures such as "land submerged", because the holm is flooded by the sea several times a year, leaving only the five houses and their respective little hills exposed above the surface of the water. On such days there is no school. The Swiss director Cristina Amrein has accompanied the children on their everyday life, taking part in their forays and their way of thinking, which she immediately takes on in her own camerawork. "Can I christen your camera? What's your camera called?" asks Henrik, and then gives the answer himself: "I know, we'll call it Mr. Proofpainter." Composed in black and white images, the documentary is underlined with piano music - some of which Mozart composed as a child.