In the blink of an eye, Kim Shin (Park Yong-ha) loses everything dear to him. His father's company goes bankrupt, his brother commits suicide, his girlfriend (Park Si-yeon) leaves him, and he himself ends up in jail for a crime he didn't commit. While in prison, Shin learns that all of this was brought about by corporation head Chae Do-woo (Kim Kang-woo), who devised the scam that brought down his father. Determined to beat Do-woo at his own game, Shin sets out to get revenge, no matter the cost. More and more people are pulled into the unforgiving battle of wits as stakes are raised, secrets are revealed, and love turns into a weapon.