sleepingbaku's manga / #grandfather's replacement(2)

Katsuya sleeps with his grandfather's former student, Miyamoto

At the party for Madoka's grandfather's, Shigekazu, retirement and Madoka taking over the firework workshop Manten Ya as the third proprietor, college student Mitsuki suddenly burst in claiming to be Shigekazu's ex-lover. Madoka is skeptical and the two argue, but Shigekazu tell Madoka to let Mitsuki accompany him as he works.