Gauche is a diligent but mediocre cellist who plays for a small town orchestra and the local cinema in the early 20th century. He struggles during rehearsals and is often berated by his conductor during preparations for an upcoming performance of Beethoven's Sixth Symphony. Over the course of four nights, Gauche is visited at his mill house home by talking animals as he is practicing.

Nobita, believing he and Doraemon had done a good deed by saving stray cats and dogs and sending them back in time by 300 million years, discover that the usage of Doraemon's Ray of Evolution had created a cat-and-dog-person society equal to Nobita's time. When an asteroid attack is set to hit the city, Nobita and his friends must save Doraemon and ease tensions between the two sides.

Nobita finds his old teddy bear among the trash after his mother partially cleaned up their shed and tells her not to throw it away. The stuffed animal is a precious gift from his beloved grandmother. Reminiscing about her makes Nobita ask Doraemon to take him back to when he was still three years old and his grandma was still alive. [edit]