Nobita Nobi wanders through a drifting pink mist near his home and finds himself in a strange forest, and when he later leads Doraemon back through it, the mist turns out to be a passage to another world. On the far side lies a planet where animals walk, talk and live like people while keeping their land green, and the pair befriend Chippo, a curious dog boy. Shizuka, Gian and Suneo join the trip just as Chippo's people learn that the Nimuge plan to seize their planet.