My Stepmom's Daughter Is My Ex

E1. The Former Couple Refuses to Say...

Mizuto and Yume used to date, but now they've suddenly become stepsiblings. Both of them agree that they don't want to do anything that'd disappoint their newly remarried parents. However, neither of them can accept the other as being the eldest sibling in the relationship. So they both agree to settle the matter with a game. Whoever does something in conflict with what people might consider normal sibling behavior, loses. Making them the younger sibling.

★ 6.6

E2. My Ex Needs Taking Care Of

After entering high school, Yume was making an effort to change her personality and looks in an attempt to reinvent herself as a model student. It was all so far so good, but there was one thing she couldn't change about herself. She was never very athletic. On the day of the physical fitness test and body measurement check at school, a melancholy Yume is approached by Minami Akatsuki, a girl from the same class. Meanwhile, Mizuto is as disinterested as ever...

★ 6.8

E3. My Ex Has a Confession to Make

It's nighttime at the Irido residence. Yume has somehow found herself with Mizuto's boxers in her possession. If Mizuto were to find out, it would almost certainly mean she would have to face the punishment of admitting to being the younger sibling. Hoping to avoid this outcome, Yume waits for Mizuto to fall asleep before heading to the bathroom to return his underwear to the laundry basket. But who does she pass in the hallway, but a bewildered Mizuto, mouth agape, with Yume's very own bra dangling from his grasp.

★ 6.8

E4. That's Not What You're Supposed to Say

As punishment for the underwear incident, Mizuto demands Yume go on a date with him. Yume is taken aback by the sudden development, but little did she know that it was all part of Kawanami Kogure's devious plan, a plan to shatter Minami Akatsuki's delusional dreams of marrying Mizuto only to become Yume's doting little sister. And how else to do it but to show her that Yume only has eyes for Mizuto?

★ 7.6

E5. The Former Couple Spends the Night

It's Mother's Day, so Yume and Mizuto go out to buy a gift together. Their mother, Yuni, is overcome with happiness to receive a gift from the two of them. Seeing how happy it made her, Mizuto wonders if it'd be nice to give their parents some time to be newlyweds together. However, there isn't much they can do for them on a high schooler's budget. So Mizuto suggests that he and Yume spend the night somewhere instead.

★ 7.7

E6. The Former Couple Goes Head-to-Head

The first midterms of the school year are upon them. Once the top scoring student in the school's entrance exam and now a talented student at the top of her year, Yume is anxious to defend her position as a model student. She is displeased, however, to discover Mizuto’s relaxed approach to studying. The two later butt heads again, over something Mizuto did during their Japanese exam. Yume berates Mizuto for his actions while Mizuto retaliates in kind.

★ 7.7