Aoki Daisuke is a fresh, new elementary school teacher, eager to help shape and guide his young students. But he got more than he bargained for with Kokonoe Rin! This saucy third grader has knowledge beyond her years, and a deep-seated mistrust and loathing of adults. She will go to any lengths to protect her friends Kuro and Mimi, including harassment, extortion, threats, and sexual blackmail. And yet, with her friends, she is kind, caring, and self-sacrificing. Can Daisuke gain Rin's trust and save her from her dark side without falling victim to it himself?