学校からの下校途中、トラックに轢かれた女子高生・サヤは昏睡状態から回復して以来、奇妙な美少女の姿が見えるように。サヤにだけ見えるその少女・ハピエルは、学校内を好き放題に闊歩し、セクハラ＆パワハラを次々繰り出す…とんでもない子だった！自らを天使と名乗り、サヤの命を守りにきた少女・ハピエルと、悪魔に狙われる不幸体質巨乳JK・サヤとのハチャメチャ学校生活が今始まる！

Saya, a high school girl who was hit by a truck on her way back from school, can see a weird beautiful girl after she recovers from a coma. The girl, Hapiel, who can be seen only by Saya, walks around the school as much as she wants and gives out sexual and power harassment one after another…it was a ridiculous child! Hapamecha school life begins with Hapiel, a girl who named himself an angel and has protected Saya’s life, and JK Saya, an unfortunate constitutional big tits targeted by the devil!