If you haven't watched episode 4 of Aki Sora, proceed with caution as this post contains spoilers.
There is no "episode 4" of the anime; however, the story continues in the manga, where Chapter 4 and subsequent volumes conclude the narrative. Overview of the Anime Series aki sora episode 4
"The Dream's End" (A Conclusion of Sorts) Format: OVA (Original Video Animation) If you haven't watched episode 4 of Aki