Nobita is extremely surprised when Doraemon suddenly randomly swaps places with him to avoid getting scared by a mouse, and Nobita asks him how he did it. Doraemon tells him he used the Replacement Mirror, and Nobita as usual becomes greedy and runs off with it, causing a lot of trouble for many people, including Gian, Suneo, and his teacher. At the end, Doraemon and Suneo are both fed up and team up together to stop Nobita.
