Haruna is convinced that school life is like a monkey mountain—all the monkeys form cliques, get into fights, and get back together again. 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?
After her politician father is disgraced in scandal, Haruna Aizawa transfers to a new school. Haruna is convinced that school life is just like a monkey mountain--all the monkeys form cliques, get into fights, and get back together again. She even meets a boy named Masaru who reminds her of a baby monkey!