Hana to Arashi no Regret

One day, Watase, a university student, comes across a cat vandalizing the flower beds of the Agriculture Department. Unfortunately, they were seen by Kashiwagi, an eccentric senior agriculture student.

Kashiwagi, who is devoted to plant research, makes disturbing threats to the cat, and Watase panics and says "I'll do anything, but please forgive the cat." At first, Watase has to follow Kashiwagi's orders and do chores, but he gradually becomes attracted to Kashiwagi, despite his unpredictable behavior. And then he finds out that Kashiwagi is gay, too.

(Source: ShuCream, translated)