Blue Box manga volume 10 features story and art by Kouji Miura.

After a hectic shopping date, Taiki takes Chinatsu to watch a beautiful sunset. With this perfect atmosphere, Taiki is preparing to tell her something important—when he’s interrupted by Chinatsu’s former teammate! Yumeka’s got nothing but venom to unleash on Chinatsu, leaving Taiki stunned. Who exactly is Yumeka, and what ruined their friendship?!