Muteki no Hito

Synopsis:

Sonokawa Junpei, 19, supports his mother and younger sister by working many part-time jobs. At V Line, where he works as a janitor, he finds a significant cash prize one day for anyone who can figure out how a prominent champion (a player called "M") of their online mahjong game cheats. Junpei seizes the chance to earn money for his family when this same "M" turns up at the family restaurant where he works. His plan is to make friends with 'M' (Mizuki) and expose his cheating technique. But it is obvious that the friendship portion will be difficult when he visits Mizuki's home. Mizuki's older sister informs him that he had brain damage in the collision that claimed their parents' lives. Since then, he has developed remarkable memory abilities but lost the capacity for feeling emotions. He dedicates all of his time to playing and winning mahjong online. Now, Junpei wants to show Mizuki that he is a smart and not a cheater by actually becoming his friend!