My Stepmom's Daughter Is My Ex (継母の連れ子が元カノだった)

Where are you going, Mizuto-kun?

Right back at you. Where are you going, Yume-san?

Oh? I thought you two were headed out.

We were just about to leave.

For that bookstore on Karasuma Street, by chance?

A little bird told me you like to read!

So you two must be headed to the same place.

Yume only ever goes to the bookstore or the library, after all.

M-Mom, please!

I trust you'll take care of her, Mizuto-kun.

S-Sure thing...

All righty then. You two get along, okay?

Take care!

Why did you say yes?

You heard her. She didn't give me much choice.

Why should I have to tag along with someone like you?

Whatever. I don't want you tagging along, either.

I always hated how passive you are.

Stupid geek!

And I always hated how selfish you are.

Stupid nerd!

Irido

That curry was so good!

The Former Couple Refuses to Say...

"It's things like this...!"

I'm glad you liked it.

Thanks for the meal.

Of course!

Thanks for the meal.

I'm so glad they seem to be getting along.

You're telling me.

To suddenly get a housemate of the opposite sex at that age...

I guess that sort of thing doesn't matter much nowadays.

Well, looks like I was worried over nothing!

Families come in all shapes and sizes these days.

Just because they're stepsiblings doesn't mean they can't get along.

Here you go, dear.

You get it, don't you?

Why thank you, Yuni-san.

Get what?

We mustn't do anything to upset them.

I know that.

I'll take what happened between us to my grave.

Excellent.

Look who's all high and mighty.

Since when were you this bossy?

If I wasn't like this before,

then it's certainly your fault that I'm like this now.

Huh?

Got a problem?

Apparently their daughter's gonna start living on her own.

Yeah?

Yeah, and I heard...

Beyond All Limits

I've completely reached my limit.

Something's Wrong...

Is something wrong?

How much longer do you plan on calling me by my given name like it's nothing?

You're using my given name too.

That's better than you using mine.

Not much we can do now that we share a family name.

What would you suggest I call you?

That's obvious, isn't it? It's perfect.

What is?

"Onee-chan."

Huh?

We're siblings now, so addressing me as your older sister makes perfect sense, no?

Hold it, hold it, hold it.

You're the older sibling?

Gimme a break. It's the other way around.

I'm the older sibling here.

Let me put this simply, since your brain cells seem to be off duty right now.

Listen well.

Our society considers the firstborn child to be the eldest.

That's premise number one.

I was born before you. That's premise number two.

Therefore, I am the older sibling.

It's the logical conclusion. You follow?

But if memory serves, weren't we both born on November 3rd?

So we're the same age, correct?

By the day, perhaps, but that's not everything.

You must also consider the time of birth.

Time of birth?

I asked Mineaki-san in order to settle the matter.

I was born at 11:04 AM,

while you were born at 11:34 AM.

In other words, I was born thirty minutes earlier.

You with me?

Didn't Japan used to consider the firstborn twin to be younger in ancient times?

But we're not twins.

We're not even siblings in the first place.

Hey, wait a second...

We consider the firstborn to be the eldest now anyway.

Just go along with it, would you?

Thought you could fool me?

Whatever. I'm the older sibling. QED.

Case dismissed.

I'm going to be the older sibling.

The thought of being your little sister creeps me out!

Same here!

I'd take anything over being your little brother!

Wait, hang on.

What?

Glaring at each other won't get us anywhere.

At times like this, any reasonable person would settle things with a game.

Irritating choice of words, but you're right.

In that case...

How about this?

We've both accepted the fact that

we'll have to hide our previous relationship

and act like any normal stepsiblings would.

We've both been doing well so far,

but either one of us may yet slip up

and do something out of line, no?

So whoever screws up first loses.

So whoever first acts in a manner unnatural for a stepsibling

Little Brother

becomes the younger brother or sister?

Little Sister

Little Brother

Little Sister

The sense of competition engendered by such a rule

should also help inspire us to better hide our past.

So do these rules apply even when our parents aren't around?

Of course.

Also, that's per slip-up.

The winner gets to decide how the younger shows it every time.

I guess there'd be no point if it was sudden death.

Okay, let's go with that.

Then...

The game starts now.

Wai—What are you doing?!

Oh, what's wrong? Isn't this normal sibling behavior?

I get it now...

It seems he's finally realized the true nature of the rules I laid out..

Even if it's an obvious provocation,

I'm not allowed to show irritation over any action

that would be considered normal among siblings.

Such a reaction would fall into the category of "unnatural for a stepsibling."

In other words...

This was just a ploy to get under my skin!

Stupid girl... She proposed those rules just for that?!

She's twisted!

This is bad.

My own personal Pandora's box is right there!

That drawer contains things I can't let anyone see!

What do I do? What do I do? What do I do? What do I do?!

Forgive me...

I can't bear to fight with you any longer.

If I've upset you, I apologize.

I'll even get out of your sight.

So please...

Can we put this behind us?

Irido-kun...

Yup, you're out!

Siblings don't call each other by their last names.

B-But you're out too, aren't you?

Wanting to bury the hatchet is completely normal for siblings, don't you think?

Now then, since this is the first round, let's keep it simple.

Just say it.

H-How should I say it?

However you'd like.

O-Onii-chan...

Well, you've learned your lesson.

Now you know not to mess with me.

You may fancy yourself a hardcore mystery fan,

but you and I simply aren't on the same level up here.

You never...

used to be this mean to me back then!

There, there.

You're right. I'm sorry.

Onee...

Nee-san.

Th-This is the part of you I...

I always hated how you flip-flop like that!

Stupid Onii-chan!

You both look wonderful!

Rakuro High School Entrance Ceremony

Rakuro High School Entrance Ceremony

It would've been one thing...

...if we were only going to the same school.

Squeeze in closer, you two.

New Students Class Assignments

Student Name Irido Mizuto Irido Yume Egami Akika Ogata Shogo

Pronunciation I-ri-do Mi-zu-to I-ri-do Yu-me E-ga-mi A-ki-ka O-ga-ta Sho-go

But we're in the same class.

With the same surname.

I guess pretending to be strangers...

Say cheese!

...is kind of out of the question now.

Rakuro High School Entrance Ceremony

We're walking to school separately starting tomorrow, got it?

That goes without saying.

Anyway, shouldn't you be more focused on making friends?

This is your high school debut.

My high school debut?

I'm the only one in the entire school who knows you used to be a total nerd.

It's the perfect time to reinvent yourself.