Captive of the Female Princess ~The Uniformed Girl of the Abandoned School~

Sakuraoka Academy is a prestigious private school located in "Kaohsiung" in the central mountains, proud of its hundred-year history, attended by many children from respectable families.
The protagonist, Furutaka Ryusuke, is a young man who has lost everything.
He lost both parents at a young age, and the grandfather who raised him also passed away.
He was injured in a traffic accident, and his dream of playing tennis was shattered.
Ryusuke was supposed to go to live with overseas relatives he had barely met, but in the end, he accepted an invitation from a friend of his late father, who served as the chairman of Sakuraoka Academy, to attend the school.
Ryusuke had lived in Kaohsiung as a child, and although he was somewhat confused, he accepted the invitation.
Starting a new life at the academy, Ryusuke met a cute girl named Kuramoto Yui.
When Ryusuke lived in Kaohsiung, there was a girl he often played with. She looked just like Yui and had the same name.
Although Ryusuke was overjoyed at the reunion, Yui seemed to have forgotten about him.
However, the two quickly became close.
In addition, Ryusuke also met beautiful girls such as the chairman's daughter and archery club member Toya Yuru, and figure skater Tateishi Nao.
Although he couldn't find anything to devote himself to anew, it seemed he could enjoy a pleasant student life.
Sakuraoka Academy had an abandoned old school building.
It was the only building remaining from the school's founding, and due to years of disrepair, it was now off-limits.
For Ryusuke, the old school building was a place of important memories.
He and that girl used to sneak in to play.
One night, Ryusuke saw a figure sneaking into the forest through a window.
Following out of curiosity, Ryusuke discovered that the figure had entered the old school building.
As if drawn in, Ryusuke also entered the old school building.
Then Ryusuke witnessed a girl being gang-raped.
What was unusual was the girl's excessively lewd appearance as she indulged in pleasure—and himself, as if manipulated by invisible threads, assaulting the girl.
The mysterious girl encountered in the old school building invited Ryusuke and everyone connected to him to a maddening feast of incubi.
What is the secret of the old school building?
What does the mysterious girl, visible only to Ryusuke, want Ryusuke to do?
And what are the people trapped in the old school building, frozen in time, thinking?