Coy and self-conscious high school student Karin Karino never paid much attention to boys until she met Kiriya, a popular student from a nearby boys' school. Karin and Kiriya embark on a romantic journey despite Karin's classmate Yuka's best efforts to sabotage their relationship, but Karin soon learns that living happily ever after isn't on the curriculum when she becomes Kiriya's center of attention, as well as embittered Yuka's bull's-eye on her dartboard of hate.
Blood proves to be thicker than water when Kiriya leaps straight into the path of danger to save his father from being hit by a speeding car. But will this selfless act be enough to mend the chasm-like rift between father and son? The situation intensifies when Karin learns a secret about Kiriya's dad that she is asked to keep from her beau!