While Nobita is slumbering peacefully in his room, he suddenly feels as though the ground beneath him is shaking violently, as if an earthquake were about to strike. Suddenly, a tiny rabbit from another dimension called Chamii bursts through the doorway between dimensions using a hammer and makes its way into Nobitas sleeping quarters via the floor. As Nobita awakens, Doraemon hears someone stealing food from the kitchen fridge. It turns out that the thief is none other than Chamii, who gets caught by both Doraemon and Nobita. She then reveals a hidden passageway leading to a spaceship that lies beneath Nobitas floor. After they enter the ship, they find themselves on the Koya Koya Planet, where they encounter a young boy named Roppuru.