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Nobita has been having a weird dream about a boy named Roppel and his strange companion Chami traveling in space. By a twist of fate, he met them in person where it turns out that they are real and that they were being pursued in space, causing their space vehicle to malfunction, connecting the space vehicle itself with Nobita's room. They journeyed to Roppel's planet and amidst their enjoyment, Nobita and Doraemon pledged to help Roppel's planet free from their oppressors.
Nobita finds an stray dog and brings him home, little does hi knows that the dog is actually a prince in his homeland, a world appart deep in the african "Smokers Forest" were the dogs evolved and have their own empire, so he and his friends take on a journey to take back the young prince to his homeland but when they get there things have changed...