Nobita's escape fantasy gets so weird that Doraemon ends up building a time machine to find unclaimed land, because the actual problem, nowhere left to run to, is too real to solve any other way. The movie takes that desperate logic seriously enough that it pivots into genuine prehistory, where a kid and his robot cat have to save a tribe from a dinosaur-shaped god while still carrying the weight of their original problem home. Comedy lives in that collision between the absurd solution and the real feeling underneath it.

Nobita's latest escape fantasy hits a wall: there's nowhere left to run. Every inch of the world already belongs to someone. His friends soon want to run away too, and even Doraemon joins them. One solution emerges, mad as it sounds. They travel back 70,000 years, to an age before any people lived there, and build their own private paradise on free land. After enjoying that freedom, they return home. Days later they meet Kukul, a caveman accidentally carried into the present. His Hikari tribe has been attacked and captured by Gigazombie and the Kurayami tribe, so the group heads back to prehistory to rescue them in a comic fantasy adventure.