From the back cover:
Sano’s little brother Shin returns! Shin has become a rising star of the high jump, and he’s determined to prove himself by beating his older brother. But that’s not the only blood on the track… the one coaching Shin is their father! Can Mizuki just sit back and watch as Sano fights the father he turned away from… and the brother who never forgave him for doing so?
The blurb for this volume is misleading, since Sano’s dad doesn’t make an appearance until the last page of the final chapter. His influence over Shin does majorly preoccupy Sano this volume, though, since the dad has a history of pressuring his kids.
The romantic momentum does suffer a little with a plot more focused on Sano’s family, but it’s not completely abandoned, and I thought the balance worked well. I’d still like to see more of the actual high jump competition, but using it as a backdrop for Sano to express his brotherly concern also works for me.
I’m still not sure whether Nakajo has an actual plan for the ending of the series, but I appreciate that things no longer feel as pointlessly episodic as they did around volumes 11 and 12. Maybe she’s gotten better at integrating relationship progress with her random ideas. In any case, I’m happy to be truly enjoying the series once again.