From Baka-Updates:

Keita, a highschool student, witnessed a kiss scene between Shin, his close friend and Megumi senpai, a repeating student in his class. Although senpai is cute, he's a guy and when Keita criticized that, Shin started to cry and said: "Because I fall in love with him". When looking at his best friend whom he's proud because of his good looks, being changed completely, Keita's feelings get confused...