Goodbye My Accomplice(2019)

Sayonara Kyouhansha

On a winter day, he fell in love with a man who he knows nothing about, including his true name, age, or job... Hajime is the son of the CEO of a major automobile manufacturer. He's the ideal star student, but he's hard to approach and is a loner in his class. As he passes his days with unending boredom, he meets a mysterious man wearing a suit. The man calls himself "Hirose" and jokingly tells Hajime that he's on the run. Hajime takes an interest in Hirose and visits him from time to time to see how he's doing...
This is an "unusual" love found by a lonely high school student. Witness a sentimental love story about two guys who are far apart in age centering on youthful adolescence and their struggles.

(Source: Renta!)

Note: Includes one bonus chapter.