Tsumasaki Ni Kourozu (manga)

One day, college student Iwai receives an introduction for a job as an assistant to a mycologist. Upon his arrival, he is met by Murota, a seemingly moody and unsociable man. Iwai is uneasy at first, but he finds he enjoys the days he spends coming into contact with a world previously unknown to him, as well as looking after Murota when he forgets to look after himself.

And, in the midst of it all, Iwai realizes his heart is gradually being drawn to Murota...