Young-ho doesn't have any dreams for his life. He has been studying for three years to enter a university. He decides to send a letter to his childhood friend So-yeon. But her younger sister So-hee receives the letter instead of her sick sister. So-hee writes back to Young-ho, pretending to be So-yeon. Meanwhile, So-hee takes care of her sick sister and also runs a secondhand bookstore with her mother.
In the 1990s, when Go gambling fever swept Korea, Gui-su loses everything because his father gambled obsessively until there was nothing left. Left all alone in the world, Gui-su meets a mentor and Go teacher, Il-do, and goes through vicious training to become the grandmaster of Go. He sets out for revenge on the world that destroyed his life, but soon finds himself chased by an unknown loner pursuing his own vendetta.
A professional GO player gathers a team to help him carry out his revenge against the man who killed his brother.