Ten years ago, Amano Hikari disappeared.
But it's not just her, her whole class in the girls' school had disappeared entirely. Furthermore, it's on weekday.
Thirty people had disappeared from the school at daytime.
It naturally became news.
The police had began to search using several hundreds of people but there was no single evidence remaining.
It's natural as they were summoned to another world with some paranormal power.
Though the event was reported for several weeks, the public's attention was moved to a different location when there's no progress appearing.
The police also gave up at the mystery of disappearance after one year.
The families also made a group to conduct their own investigation but a normal person can't search out what the police hadn't.
The activity became small gradually.
However, Miyuki still continued to believe.
Her gentle sister won't just disappear by herself.1
She was young back then but her feelings of belief for her sister was strong.
Several years later, a letter reached Miyuki.
The paper was sloppy and there's no name of the sender either.
「Could this be…!」
Though it's a really suspicious letter, Miyuki was convinced that it's her sister by just seeing the written character.
She went back to her room immediately and took out her sister's notebook.
『It's been a while, Miyuki. It's me2』
「It's really nee-san!」
Then she compared the characters and concluded.
『You may not believe it but I'm in the otherworld right now. It's a fairy tale world』
Miyuki knit her eyebrows.3
『This letter is my special ability, and I can only send this thing to the former world once』
However, her body began to tremble while she's reading.
『I have to defeat the Maou here. And, my existence in the former world disappears when I die here』4
The names of the students who have died have been written after that sentence.
「No way, I can't remember them…?」
She looked through the letter a lot of times.
There are houses where Hikari had played from written in there.
However, she can't remember the faces no matter how much she tried.
Miyuki continued to read while feeling impatience.
Then, she read something unbelievable.
『I might die too』
Miyuki's body stiffened the moment that sentence caught her eye.
However, she continue to read ahead.
『We went to defeat the Maou but there's a traitor among the allies. Her name is Nakusa Youko』
「Nakusa, Youko…that person!」
Fortunately or not, she was able to remember her face immediately.
In short, that woman betrayed her sister and is now living.
Miyuki felt anger rising inside her.
『She was on the side of the Maou on the last moment. A lot of companions have died because of that and I might die too』
「N-No way…I don't want to forget nee-san!」
Unable to control her feelings, Miyuki gripped the letter.
『Though I felt embarrassed ignoring everyone and writing this letter, I'm glad I wrote this., Thank you for everything so far, Miyuki, I'm glad I was with you』
The letter was cut off there.
「Nee, san…」
Miyuki then crumpled the letter she's holding.
However, she stood up and put it aside to valuables.
「I'll definitely search for you」
Her eyes right now is much more determined than before.
Afterwards, she found Nakusa Youko what was with Hikari.
She lost her cool of course but only Hikari is the one reported.
The remaining students have disappeared completely.
The announcement of the police is that they are supposed to be kidnapped by a mystery man.
It was the whole female class before but it's not impossible to be a case of two high school girls.
Miyuki can't believe it naturally and went to meet Youko directly.
She was in the hospital and was being examined.
「Are you Nakusa Youko-san?」
Restraining her feelings, Miyuki asked.
「Yes, you're Hikari-san's little sister, aren't you?」
「Can you tell me where's nee-san?>」
「I'm sorry but I don't know it. It's because I was confined in a private room…」
Youko speaks like it's a reported information.
It seems that she doesn't know that Hikari sent a letter.
(But, she'll only evade if I question her right now)
Miyuki thought so she gave up and pulled back.
「Understood, please take care」
「It's fine, I'm also worried about her…」
Miyuki kept herself, enduring not to shout against her.
「Excuse me…」
They didn't meet for a while but Miyuki kept collecting information about Youko.
Then, Miyuki learned that she had returned to society and became a teacher.
(Suspicious, why a teacher…furthermore, this class!)
She took charge of the class in the co-ed high school that's only females.
(Could it be that they'll try to go to otherworld again?)
Miyuki imagined so as she decide to enter the school.
It's good luck that it was a nearby high school so it's not unnatural to enter it.
Then, Youko was summoned into the otherworld just like expected.
◆ ◆
「Why have you kept quiet until now?」
The only one who asked among the silence in her talk was Hironobu.
「Sensei knows the system of this world is an adult」
「Then?」
「When she's exposed, she might be massacring the elves at worst case scenario」
「Was her status reset?」
When Hironobu looked at it, there's no number of her fighting on the otherworld.
「The first one was when Dark Satan was summoned right?」
「U, right…」
If there's information leak, then there should be a contact method.
Hironobu's ability was also useless when first attacked by dark satan in the grassland.
「Also, when I received the attack from dark satan and fell off the cliff, I saw Sensei's face laughing at me」
「Wha…」
「You won't know if you didn't check it. Then dark satan tried to kill her」
「Was that also Sensei's plan?」
「She tried to exclude me and used everyone else's value. I don't get something」
Hironobu became silent.
The sensei that helped him is the one who tried to kill his childhood friend and her sister.
He can't open his mouth in shock.
「According to the Mugs, it needs enormous magic power to revive the Maou. Something coming in your mind?」
「When you talk about huge magic…there's only one thing coming up」
「You know something?」
Hironobu pulled his body back from Miyuki's press.
「It's my special ability, that…」
「You should've said this earlier」
Hironobu gave up and spoke as her tone is like a trap.
「"Sex Reward"I can raise the status by those I have sex with. I think that's why sensei raised her status」
「Eh, Ha? S-Sex!?5」
She didn't expect those words.
Miyuki stiffened and blushed.
Then Valeria had noticed something.
「That's right, we can go with this! We can use the first method!」
「The first method, could it be…」
Hironobu noticed it too, he then looked at Miyuki in front of him.
Then, Valeria put her hand on the shoulder of the two.
「The two of you should have sex to defeat the maou!」