Kwon Si-Hyun bets his life on a dangerous game to seduce Eun Tae-Hee. His target is 20-years-old and believes people that are swayed by love are pathetic. After Eun Tae-Hee meets Kwon Si-Hyun, her view on love changes. Based on 18th century French novel "Les Liaisons dangereuses" by Pierre Choderlos de Laclos.

Set at a prestigious private high school in Gangnam, Seoul, South Korea. Eun-Byeol is a popular student at the private high school. She goes missing and returns, but she has lost her memory. She tries to find out the truth.

Two childhood friends grow up supporting each other through the difficulties of poverty, then meet again years later and stand by each other as they rise through the ranks of society. After marrying into a wealthy business family, Kim In Sook's life becomes a living hell. Seen by her in-laws as a gold-digging intruder, she is pushed to the margins. When her husband is killed in a helicopter accident, her mother-in-law takes away In Sook's beloved son. Enter Han Ji Hoon, an old friend of In Sook, and powerhouse new family lawyer determined to put a stop to In Sook's mistreatment. In Sook finally retaliates by launching a bold plan to take over the family company, and Ji Hoon supports her no matter the cost. In the midst of their battle for survival, their hearts are drawn together in a passion that could end up costing them everything.