Gray to Blue no Ai made

Koutarou, a high school teacher who is ordinary in both looks and attitude, has a reputation as a “boring man”.
Koutarou’s father-in law, Koushi, who somehow remains charming despite being over 50 years old.
Koutarou’s student, Sayotani, who with his youth and beauty goes through one man after another.
These three people who are ages apart connect with each other through Koutarou...
A love story about three men who remain clumsy about love despite their age!

(Source: Printemps Shuppan, translated)

Note: Includes one extra chapter.