15 years after the first part. Tsukikase lost his mate Jun. He now is a High School Teacher and found his second chance mate. Hinoura is a High School student who thought he was a Beta but in reality turned out to be an Omega. He is Tsukikase's second chance mate. They ended up together after Hinoura graduated high school and he got pregnant with Tsukikase's baby and gave birth to him.
Happy end? Kind of. I would have preferred Jun to still be alive though.
Tsuki no Ura wo Koete ~Omegaverse~