Time is before the war.
Daisuke Togitsu, a young man who is a former magazine reporter, visits a dubious Western-style building on a hill overlooking a rural mountain village.
Waiting for him in the luxurious Western-style building was Sumimi Kiriya, the hostess of the mysterious building, and her beautiful sisters, her daughter.
“You have been chosen … to be the only man to have a daughter and child with Kiriya and get all of this Kiriya family. This is the old tradition of my Kiriya family. Embrace my four daughters as you like, make a “contract” and conceive them.
” I will stay.
A lewd and intimate contact with the sisters, which is held every night under the name of “Yoru”.
And the forbidden memory with the fourth daughter, Fujino, who should have passed away early.
What is the mystery hidden in the blood of the Kiriya clan? What is the fate of waiting for Daisuke?
The story of the fluttering Eros that unfolds in the Immoral Hall.