Princess Sisters!~All four sisters are married to you~<With early booking campaign benefits> (related items of this title)

The main character "Kaburaki Ryo" who used to live a wealthy life.
After the death of his father, who had been working on business for many years in the "Republic of Keynesburg", which belongs to a small country county in Western Europe、
The family went bankrupt and lived a poor life while holding a part-time job.
the mysterious maid sakura appears before him

"I would like you to support my Lord's study in Japan."

The maid who asks for an explanation to sign the contract early.
I mean, why me......?
Although he is reluctant, it is a request related to the Republic of Kainesburg related to his father, and most of all, he is blinded by the high salary and undertakes it.

on that day, sakura called ryo, who was waiting for her arrival at the designated mansion outside of town.

"Hi, hi......Hi, hi, Ehu, is it a mansion?　…...Please come right in front of the station."

And that.
Ryo rushes to the front of the station for something without defying the client's order.
While being hit by trouble with the girl in various places to go, when you finally merge with Sakura there is 4 sisters who are the source of trouble.
It is as if "You are at that time" to fulfill the reunion.
I mean, not many......?
While such an idea is in the head it is given a mission to take care of all 4 sisters of "Flora", "Anise", "Cheryl" and "Amy".

However, the true intention of this study abroad……
The king, who was deeply indebted to Ryo's father's achievements in the Republic of Kainesburg, wanted to invite Ryo to the royal family.
Therefore, all 4 sisters who are his own daughters were made fiancé of Ryo, and it was decided to carry out a big matchmaking project in which the princess who was chosen as a bride from Ryo became the first to succeed to the throne.

At first it was the princesses who were showing a disillusionment, but、

"So, I'm fine with choosing Amy without worrying about the order or anything.And then Amy is the future queen."
"How about...?　When I was flirting with me a while ago, I became a cock ging ging."
"I'm not saying disgusting!　If it is the fate of those born in the royal family, wow, I......"
"Fufu ♪ The feelings of our sisters are surely the same.After that, at the discretion of Ryo-sama"

Thus, "matchmaking project with cohabitation life" with sisters who are princesses began―――

かつては裕福な暮らしを送っていた主人公「鏑木亮」。
西欧の小国郡に属す「カイネスブルク共和国」で長年事業を手掛けていた父親が病没後、
家は破産しバイトを掛け持ちしながらの清貧生活を送っていた。
そんな彼の前に謎のメイド「サクラ」が現れ

「あなた様には我が主の日本への留学をサポートしていただきたいのです」

説明も早々に契約書にサインを求めるメイド。
というか、なんで俺……？
うさんくさがりながらも、父親ゆかりのカイネスブルク共和国絡みの依頼であり、何より高給に目がくらんで引き受けてしまう。

当日、指定された町外れの屋敷で到着を待つ亮にサクラから電話がかかってきて

「ひ、ひー……ひ、ひっ、えふっ、お屋敷ですか？　……すぐ駅前に来てください」

とのこと。
クライアントの命令には逆らえず何事かと駅前に急ぐ亮。
行く先々で女の子とのトラブルに見舞われつつ、ようやくサクラと合流するとそこにはトラブルの元である4姉妹が。
まるで「お前はあの時の」的な再会を果たす。
というか、多くない……？
そんな考えが頭をよぎる中「フローラ」「アニス」「シェリル」「エイミ」の4姉妹全員の世話をしろというミッションが与えられる。

しかし、この留学の真意は……
カイネスブルク共和国での亮の父親の功績に大変な恩義を感じていた国王は、亮を王家に招きたいと考えていた。
そこで自身の娘である4姉妹全員を亮の婚約者とし、亮から嫁に選ばれた姫が王位継承権一位となる一大お見合いプロジェクトを実施することにしたのだった。

初めは気乗りしない様子を見せていた姫達だったが、

「だから、順番とか何も気にせずにエイミを選んで平気だよ。そしたらエイミが未来の女王様かー」
「どうかな～？　さっきあたしとイチャイチャ♪　ってしてた時もちんこギンギンになってたし」
「嫌とは言っていません！　王家に生まれた者の宿命であるならば、わ、私は……」
「ふふ♪　わたくし達姉妹の気持ちはきっと同じです。あとは亮様のご随意に」

かくして、お姫様である姉妹達との『お見合いプロジェクトwith同居生活』が始まった―――