At a rural middle school, two boys and girls swore an eternal friendship. They became a "shared fate" (best friends) with one dream in mind — but their relationship didn't particularly progress, and two years passed without any major changes!
Even as second-year high school students, the cheerful girl Inuzuka Hiiro, who has never experienced her first love, and the flower-loving, plant-like boy Natsume Yuu, remain unchanged. They continue to be peaceful best friends in their gardening club, just the two of them.
However, when Yuu reunites with his first love from the past, their relationship begins to shift unexpectedly. Will Hiiro, who is starting to experience love, manage to break free from her role as the "ideal best friend"?