Mysterious Girlfriend X, 6, Paperback

As the school year wears on and the warmer months arrive, the boys enjoy the sight of the girls in their softball uniforms and swimsuits. Tsubaki invites Urabe to watch the fireworks from a place that holds special memories for him. Oka describes how she and Ueno first started dating, and Urabe comes clean to Tsubaki's sister about their relationship. When Urabe "sees" an important event from Tsubaki's past, she makes him an offer that will bind them together even more closely...