(from ebookjapan):

A coming-of-age tale of two brothers, Mitsuru Adachi and Tsutomu Adachi!　Early 1970's --- the eve of the golden age of manga.

Mitsuru Adachi is 19 years old. Tsutomu Adachi, 22. Takeshi Arima, 16. The unprecedented joint life of these three manga boys, who were still nobodies, was about to begin. Takeshi Arima of "Ren-chan Papa" depicts the coming-of-age drama of men who devoted their lives to manga, centering on his own sensei Tsutomu Adachi, the man who made Mitsuru Adachi a mangaka!