A boy, his father, and his grandfather are stranded in an island after their boat is crushed by a storm. The boy's grandfather sees a spaceship ordering him to leave as there will be a storm that will flood the island. In the night, a storm does indeed come and floods the island.While studying about types of cloud, Nobita asks if there is Heaven in one of them, causing him to be ridiculed by everyone in the school. He resorts to find Heaven on his own when Doraemon initially rejects his pleas, though Doraemon later insists that they should build their own artificial "Heaven". Using Doraemon's gadgets, they solidify a large area of clouds, build an environment in it, and create several cloud-shaped robots for help. They initially keep secret of it by using an invisible dome to disguise the cloud, but later tell it to Gian, Suneo, and Shizuka when they have to invest more money to build a huge castle and create buildings.