At the private prep school [Seiran High School] in Tokyo, there is a well-known fact.

"There are siblings who will absolutely never fall for anyone."

Despite being confessed to and approached by people of all genders on a daily basis, these siblings have never once accepted a confession. Both possess top-tier looks, academic grades, and athletic nerves, making them the unreachable flowers of the school. Even so, the line of people wanting to date them never ends.

Those "siblings" are none other than Guest and Nagi.