Ojisan, Ore ni Koishite Kudasai

Akihito Kusunose, an elite company employee, has a nephew named Ren Kusunose, who joined his workplace as a new employee. When Akihito was in high school, he was confessed to by Ren, however, he disregarded his confession as a misunderstanding typical of adolescence.

After 5 years, he reunites with Ren, only to find out that his feelings for him never faded away. His cute nephew starts showing his true colors and Akihito becomes self conscious of him but as his uncle, he is unable to reciprocate his feelings. One day, when they are alone in the office, Akihito compliments Ren on his work, and he is so elated that he kisses Akihito in the spur of the moment. Akihito shuts him down, but he begins to realize that his feelings for Ren are changing. What will happen to their long-standing forbidden love?

(Source: Houbunsha, translated)