I Don't Cry.

Himeno Aki, youngest member of idol unit "Za-G," is frustrated with the group's decline in popularity, and the other members' lack of enthusiasm. To top it all off, their manager suddenly steps down. Replacing him is Kasahara, a man with a soft smile and an air of unreliability. Former idol and manager; a chance encounter with destiny. Set in the same universe as [union](https://mangadex.org/title/011f25ed-2e8a-4c1e-8ce8-2e699c2c7c37/union), the two stories are not exactly related, although there is some character overlap. Source: MangaUpdates