Fuyukara Kururu | ふゆから、くるる。

"Eh? What do you mean that Shihon-chan might die? Eeh? Shihon-chan's head has gone missing?"

It seems Shihon-chan's headless body was found in the meditation room.

"B-but, the neck can still be reattached within 48 hours right? Eh? The head can't be found!? S-somebody hid it? And you don't know who? B-but that's..."

A murder isn't unusual. After all, there's at least one bloodthirsty killer at school.

Murdering people is fine and all but it's considered a taboo that must be never violated to decapitate and hide their head.

Because one can never be revived if so. I can't believe someone resented Shihon-chan enough to kill her in a way that would prevent her from being revived.

If her head isn't found within two days, she'll really kick the bucket!

That's a reality I absolutely refuse! Now's not the time to cry or be confused!

There should be something that I am capable of!

"That's something I haven't done yet but... I-I!"

I'll find Shihon-chan's head without fail!

"Say hello to the great detective, me!"

A boarding system school isolated from the outside world.

--And there do the immortal girls live.

The time it takes for them to become an adult is the same time it takes for them to deage and become a baby, they grow up until they become an adult once more and then do they deage again⁠—a cycle that's being repeated.

There's only one condition in order to graduate from school. One needed to be deemed a prodigy by someone observing from the outside. The moment that verdict be handed down, the girl's graduation would be recognized and she would disappear from school.

The immortal girls' peaceful school life would be greatly disturbed by a certain murder case.

Why are the girls immortal? Why do they grow up and then age backwards? How long were they locked up inside the school? Why can they be resuscitated even if their heads are decapitated? What happens to girls who were never deemed a prodigy? What is happening in the outside world? Why are there only girls? Where are the males? What does it mean to die? What does it mean to live? What is life?

For what purpose does life exist?

--the key to this case is a needle.

Wool needle. Knitting needle​. Sewing machine needle. Silk needle. Pongee needle. Gas needle. Futon needle. Western-style clothes needle. Bait needle. Marking needle. T-Pin. Triangular leather needle.

It is the needle that would weave the immortal girls' death.