Tooru transfers to an all-boys school and receives a warm welcome. Little did he know, his classmates had nominated him for the academy's "Princess System." He must dress as a girl at school events in order to lighten the stolid masculine atmosphere.
Toru, Yuujirou, and Mikoto are summoned to the Student Council, where the Student Council members are all introduced to Toru by the president, Arisada. The president presents to Toru all the benefits of becoming a princess – after hearing which, Toru readily accepts to be a princess.
The three Princesses are to cheer for all the clubs, for the local preliminaries. Arisada also tells them that they are all to go for cheering all the clubs which win the preliminaries (and also those which go ahead and win the national finals) or the princess benefits will be cut - Arisada has g...
Even though it is summer, the Princesses still have to cheer for sports teams and other clubs. Even Mikoto is called back for Princess work. As the princesses get ready, Sakamoto also accompanies them. As they are moving about, Toru has the creepy feeling that the Princesses are being watched.
Finally getting some free time, Toru and Yuujirou start with their summer homework. But they find some problems difficult to solve and so decide to go to Sakamoto's house to ask him for help (Sakamoto had invited them over earlier). they are also hopeful of meeting the famous older "Sakamoto-sama".
The Princesses have to put on a song and dance opening act for the choir group at their school, but there is one small problem: Mikoto cannot sing. During practice, Toru meets his cousin, who wants him to come back and marry her.
The director of the board who is in charge of the school comes to visit after inheriting the position from his father and is shocked to find out about the Princess system. So shocked, that he seeks to remove the system entirely.