"Izumi Tomohiro," appointed student council president by lottery, initially focused on safety and handled his duties smoothly. However, he gradually developed a sense of responsibility and even became active enough to spend weekends with other officers. One day, Tomohiro was forced to participate in a doujinshi event as staff for a personal circle. After selling his books, he left his seat to buy a drink. On the way, on a whim, he stepped into the self-published works area and witnessed someone who shouldn't be there...? This is the story of a girl who is not the main heroine, a story that "branches off" from the main plot.