As he graduated from junior high, Nagito Senda began dating Kiri Asatani, but he got dumped when they started high school. While recovering from his broken heart, he saw Nozomi Takane, a girl in his class, being harassed by a pushy club recruiter, and decided to help her. The two quickly grew closer as they sit together in class and go to and from school together. One day, as the two were cleaning the library, Kiri comes up to Nozomi and asks,
"Can I borrow Nagi-kun?"
When Nozomi asked Kiri about her relationship with Nagito...
"I was Nagi-kun's ex-girlfriend"
"Well from now on I'll be his new girlfriend."
Now that both girls have declared themselves, what will be his real intention? Sparks will fly in the game between the ex-girlfriend and the current girlfriend.