継母の連れ子が元カノだった, My Stepsister is My Ex-Girlfriend, Mamahaha no Tsurego ga Motokano datta, My Stepmom's Daughter Is My Ex, Step-Exes, Tsurekano, 계모의 자식이 전 여친이었다, 继母的拖油瓶是我的前女友, เอาแล้วไง ยัยแฟนเก่าดันเป็นลูกสาวแม่ใหม่, Дочь моей мачехи — моя бывшая девушка, La hija de mi madrastra es mi ex-novia., Mamakano, 連れカノ

Ah, high school. Is there any better place to start fresh after a horrible middle school relationship? Nope! Not unless your ex ends up at the same school as you and is now your stepsibling. What was supposed to be a sanctuary of peace where I could avoid ever seeing her again has become a living nightmare! Everywhere I look, I see her—in my house, in my school, in my class. There's no escape! She even claims that she’s the older sibling. Like hell she is! But I won't lose to her. After all, I'm the older brother in this new family situation. That’s right, we’re family now. No matter how much we may have thought we loved each other before, we saw one another’s true colors and realized we weren’t meant for each other. That’s why even though we may keep up a buddy-buddy sibling act for the sake of our parents, things will never go back to the way they used to be.