Touma had admired Celica ever since he was young. He always went to watch her gaze lonelily into the distance from the tall tower and nicknamed her Rapunzel after the princess from the fairy tale. They did not talk to each other, and only verified each other’s presence each day.
This daily routine changed when her father allowed her to go outside for the first time. When she was walking around taking in her brand new surroundings, a speeding truck headed straight for her. Luckily, Touma was able to save her just in time. It was actually an absurd trial planned by her father, who asked that he marry her because he had passed it. As they had been attracted to one another since long ago, they exchanged vows and became a married couple.
However, just as Touma was about to begin a wonderful life with the pure and naive Celica, an unbelievable secret was revealed: she had the blood of a succubus inside of her!