The main character, Kaburagi Ryou, once lived a wealthy life. But after his father, who had a business for many years in the Republic of Kynesburg in Western Europe, died of illness, Ryou became bankrupt and struggled to survive while working part-time. One day, a mysterious maid "Sakura" appeared in front of him and said - "I want to support you.", and asked him to sign a contract as soon as possible. But why me...? Despite thinking that way initially, the request was somehow related to the Republic of Kynesburg, and thus, was sort of related to his father, and so he decided to accept it. Soon, there came a phone call from Sakura to Ryou to meet her at a specific location. When he went there, alongwith Sakura, there were four sisters "Flora", "Anise", "Cheryl", and "Eimi" with her, and Ryou had to take care of all four of them. The truth behind all this was that the King, who felt gratitude towards Ryou's father, wanted to invite Ryou into the royal family. Therefore, he decided to carry out a big matchmaking project in which all the four sisters, who were also his daughters, were made Ryou's fiancee, and the princess chosen by Ryou as his wife, was to become the number one successor to the throne. Thus, "the matchmaking project and a new life for Ryou, with the four princess sisters", has begun.