On the day I was dumped by my uptight girlfriend Mashiro, Yuzuki, a gal who looks exactly like her, became my step-sister. I was captivated by the little devil who does all the things Mashiro never did for me, as my life is quickly transformed into an erotic harem dream! Starting with my ex-girlfriend's sister, my best friend, and the school nurse...... I am loving my life with my yandere step-sister!

(Source: France Shoin, translated)