Due to some circumstances, Lee Taemin is stuck with having to take care of his brother's baby boy, Yoo Geun. Although, Choi Minho seems to have misunderstood Taemin's situation and began to dislike him a little, Minho just can't seem to leave the hopeless and clueless Taemin alone.

Key is Mother Nature and he's pissed that humans are trashing his precious land. He meets Jonghyun and punishes him by forcing him to change the world and make it a better place, otherwise he'll destroy the Earth.