Doraemon: Nobita no Daimakyou

ドラえもん のび太の大魔境

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...

(Source: Anime News Network)