Gray to Blue no Ai made  

Between Gray and Blue, グレーとブルーのあいまで

A high school teacher named Koutarou is described as being unremarkable in appearance and demeanor, yet he has gained a reputation for being dull. His father-in law, Koushi, defies this perception by remaining attractive despite his age. Despite their differences in age, Koutarou, Koushi, and Sayotani all find common ground through the teacher's influence.