Doraemon: Nobita in the Wan-Nyan Spacetime Odyssey

An elderly dog enters a time machine, hoping to meet the person who gave him a kendama. A time-space anomaly causes the machine to malfunction, sending him back to infancy. He is discovered by a researcher cat who becomes his caretaker.

Nobita rescues a drowning stray dog after playing with Gian and Suneo and hides him at home. He names the dog Ichi, inspired by the Japanese word for 'one' and a dog's bark. Nobita starts playing with Ichi using his kendama.

Nobita also adopts a stray cat named Zubu after a rainstorm and brings him home. The growing menagerie raises Nobita's mother's suspicions, and she checks Nobita's room.

To avoid getting caught, Nobita and Doraemon use the Anywhere Door to travel to the mountains. There they discover abandoned pets endangered by deforestation and realize they must act to help them. This encounter sets the story in motion.

They decide to relocate the animals 300 million years into the past using the Ray of Evolution, enabling the animals to operate a food-making machine. Nobita promises Ichi that he will return, and the group prepares for the journey. The plan shifts the animals' fate far into prehistoric times.

On the next day, a time-space anomaly lands them 1,000 years after their intended time. The dogs and cats have overused the Ray of Evolution and built a futuristic, civilized society. Nobita and friends must wait for their time machine to be repaired.

While exploring the future society, they meet a gang of teen thieves—Bulltaro, Duk, Chiko, and their leader Hachi. Nobita suspects Hachi might be Ichi, given the resemblance and time gap. Tensions rise as loyalties are questioned.

The group visits an amusement park believed to secretly imprison their parents. They drill into the park and discover a room housing a time machine. Guards ambush them, Doraemon is captured, and the others are imprisoned.

The government predicts an asteroid cluster will strike Earth and orders Noradium for evacuation ships. Nekojara, a corrupt official, steals the Noradium to fund his scheme. This theft sparks the central conflict of the human-animal dynamic.

Doraemon wakes to Nekojara's plan to use a Noradium-powered time machine and the Ray of Evolution's devolve function to punish humans for abandoning animals. Nekojara threatens Shami, Doraemon's cat idol who is actually his minion, to force Doraemon to fix the ray. This manipulation nearly derails the mission.

Freed from prison, Nobita and friends rescue Doraemon and reclaim the Noradium. Doraemon breaks the Ray of Evolution and escapes with Shami, who turns against Nekojara after he attacks Doraemon. Nobita and Hachi stop the time machine, but a meteor strikes and sinks it, destroying the Noradium.

Hachi is submerged underwater after the machine's failure, and Nobita rescues him. The rescue triggers Hachi's memory—he is Ichi, the elderly dog from the opening. He recalls hiding a Nobita-shaped Noradium statue.

With the Noradium retrieved, the government completes several spacecraft and evacuates everyone, including Nekojara and his minions, just before the asteroid impact. The team presents the recovered statue to authorities, confirming their journey.

As the asteroid threat nears, the evacuation proceeds and the city is evacuated. Nobita and friends bid farewell to Ichi and the other animals as they leave moments before destruction.

During the credits, Nobita and his friends return to the present and say goodbye to the animals they've left behind. They reflect on the journey and the friendships formed. The experience reinforces their bond and curiosity for the future.