Haruna Aizawa thinks that school life is just like a monkey mountain--all the monkeys form cliques, get into fights, and get back together again. The school that she just transferred to is no exception. There's even a boy called Macharu Yamashita who reminds her of a baby monkey!

Macharu's best friend Atsu is really starting to fall for Haruna, especially since she's been working at the same place he works and they've been spending more and more time together. With a jealous Macharu waiting and a persistent Atsu pursuing, who is Haruna going to choose in this bizarre love triangle?