You can find the complete 25-volume run on Anime-Planet or other manga reader platforms.
While there is no official "Episode 4" of the Aki Sora anime, the confusion often stems from how the series was released across different OVA sets and its relationship to other "Sora" titles. Aki Sora consists of three total OVA episodes: one standalone episode released in 2009 and a two-part sequel titled Aki Sora: Yume no Naka in 2010. aki sora episode 4
Since the anime is so short, the best way to get the full experience is through the source material. You can find the complete 25-volume run on
– A two-part sequel that explores more complex emotional tensions and introduces the feelings of Sora's twin sister, Nami. Since the anime is so short, the best
– This was bundled with the third volume of the manga and introduces the core taboo relationship between siblings Aki and Sora.