High-schooler Miki Yoshida has made a vow: for her senior year at her Fukuyama high school, she has resolved to become a more assertive, decisive person. This new resolve is quickly put to the test when she meets Hiro Sakurai, who has just transferred into the school. Taciturn and more than a little weird—he can be seen secretly observing people and taking notes on them with some zeal—Hiro immediately gets Miki’s attention, and, despite Hiro’s protests, she resolves to befriend him and, if possible, figure him out.