The story begins with Nobita facing immense pressure from his mother about school and from his teacher over unfinished homework. Feeling trapped, he declares he wants to run away from home. Shizuka, Gian, and Suneo initially humor him, but Nobita is serious. With Doraemon’s reluctant help, they use a "Bypass Tunnel" to escape to a —7,000,000 years ago, long before humans arrived.
However, viewers should be cautious of low-quality machine-translated subs, which ruin emotional scenes like Kukuru’s farewell.
Doraemon suggests a radical solution: they will travel 70,000 years into the past, to an era before Japan was even inhabited. Here, they build their own paradise, complete with mythical creatures that Nobita creates using Doraemon's gadgets (like Pegasus, the Griffin, and the Dragon).