So I was searching around and found some info on a possible second season.
Three years have passed since the events of episode 12 and Mari and Takeru have gotten together. Both are now in the work-force having skipped college, while Ryou is in college.
Suddenly Akari and Hikari return, the problem is that they return and don't know that three years have passed. Takeru is now torn and hides his relationship from the Hikari of three years ago to keep from hurting her and possibly bringing back out the destroyer Hikari. Akari herself begins to develop feelings for Takeru.
Meanwhile Mari gets more and more upset and depressed at how Takeru is dealing with Hikari's return and winds up getting drunk and sleeping with Ryou.
Yes, all of this on Season Two... Kono Minikuku mo Utsukushii Sekai:
Kimi ga Nozomu Eien
Sorry, but I'm just sitting here thinking and the characters really do match-up pretty good.
