Hanabi-chan wa Okuregachi

Recent college graduate Musashi Shinonome has inherited a pachinko hall in the Shitamachi area, and upon arriving he finds a girl asleep in a futon. She introduces herself as Hanabi Hana Ariake, a self-proclaimed perfected pachislot machine that has turned into a human. To prove it, she can transform and shoot fireworks out of her body.

Musashi also meets two of Ariake's human pachislot machine sisters, the energetic Versus Ikusa Takanawa and the loving Thunder Rai Nihonbashi. Now, the four of them must work together to make the grand reopening of Shitamachi God Heaven a success.