Series by 清野静流

16-year-old high schooler Mihane Hirata is feared for her tough looks and short temper, earning her the nickname "Satsujinki". In truth, she is earnest and completely devoted to Touma-kun. While trying to get closer to him, she accidentally blurts out a full confession. Before he even gives her an answer, the two end up trying out a three-day relationship.

A fierce high school girl gets into trouble from the very first day of school. Her teachers order her to reform the school's worst troublemaker. Their connection begins when she kicks him through a classroom window. As she spends more time around him, she starts to notice the better parts of his character. Fights, school life, and growing affection pull the two problem students together.