One day, when Hayato came back to his own room, there he meet two beautiful girls. One with the long black hair is wearing blue school swimsuit. The other one is blond and wearing white school swimsuit. For a moment, he thought he opened a wrong door instead of his room but then just the girls greet and talk to him casually like it is the most natural thing to do. Apparently, the girls are the princesses from Saintswim Kingdom and came to meet him to be his wife and make him the next king.