Nakajima goes way back with Ogiue—they were friends in junior high, back when they collaborated on yaoi dōjinshi together. Nakajima handled the writing while Ogiue did the artwork, which was a pretty solid creative partnership. Things got complicated, though, when Nakajima noticed the chemistry between Ogiue and Makita. She didn't take it well. The jealousy got to her, and she basically orchestrated something that Ogiue's never really gotten over—it's become this shameful memory that follows her around.
Years later, Nakajima shows up at Comiket with Shigeta, right when Ogiue's trying to sell her latest work. It's a rough moment for her—seeing them there brings all that old bitterness flooding back. But before she can spiral too much into it, Susie arrives and breaks the tension.
Content compiled by AnimeList.moe from publicly available sources.