Nobita trips into Journey to the West expecting a game, then watches it become real when he breezes through without fighting a single demon. The world he returns to isn't his anymore, it's ruled by the creatures he was supposed to face. A time-travel mess that turns a classic adventure inside out, leaving Doraemon stranded with a kid who has to learn what happens when you skip the hard part.
Nobita becomes obsessed with proving the Monkey King actually existed, convincing Doraemon to help him travel back to ancient China. Using a virtual reality console, they jump into a digital recreation of Journey to the West, where Nobita acquires legendary warrior clothes to support his theory. The plan goes sideways when Doraemon forgets to properly shut down the console before returning to the present day. Reality fractures. Demons begin seeping out of the game world and into modern Japan, transforming the landscape into a supernatural nightmare. With their home overrun by creatures from classical legend, Nobita and his friends have no choice but to re-enter the game to stop the invasion at its source. What started as a casual adventure to settle a historical argument becomes a desperate battle to save both worlds from collapsing into chaos. The line between game and reality blurs completely, forcing kids who just wanted to have fun to confront actual demons.