Imagine if you could float above someone you didn't like and pour rainwater on them. If you really didn't like them, you could zap them with thunderbolts. You could teach them a lesson, Old Testament style. And you could also use your powers to water crops.
In Kumo Lumo you have such a power. But with this power comes environmental responsibility. You're a cloud, obviously, and the chaps you're zapping are horned imps with eye patches. They're here to burn down the game's papercraft levels, and you're the one who's going to stop them.
But stopping them is not enough. Kumo Lumo's world is in danger, haunted by evil digital black clouds that can zap Lumo down in size. The trees need watering, the mountains need growing (also by watering) and the land's sheep need to be tended to (also by watering).