Manatsu no Eureka

1979, the start of summer, faculty member of the science department Dr. Ukai is in the middle of a lecture when he first lays eyes on a visiting student from the humanities department, Toki. Toki is quiet, with a stoic air about him... and Ukai realizes he's completely fallen for him. However, ever since Ukai lost his long-time friend and secret lover Amakata, he's been hiding the fact that he is gay, keeping his feelings bottled up for no one to know of. One day, Ukai notices a student has been following him around and trying to get closer to him. As things start to become more than just a minor issue, Toki steps in to help. Ukai offers to take him out to eat as a way of thanking him, but it seems there's more to things than just a simple meal...

(Source: Kaiohsha)