Stuck for a summer vacation research project, Nobita Nobi gets a lifeline from Doraemon: a world-building kit from a future department store, a homework tool able to form an entire second solar system. Nobita takes the role of its god, watching a new Earth cool, fill its seas and sprout its first life, and writes everything up as a diary for school. Shizuka, Gian and Suneo join in, and together they follow the first tribes and civilizations as they rise on the new world.