A student named Takumi has a crush on his senior classmate, Saki. Their relationship changes after a chance encounter on a train leads to them discovering they share similar personal interests.
According to early screener reports from Japanese adult animation circles, features:
This is the most critical section. Piracy is rampant for OVAs, but supporting the creators ensures more episodes are made.
If you are looking for a long-running anime with "Sister" in the title that might reach 14 episodes or more, you may be thinking of:
