Set in the microcosm of a school mirroring a jungle-like society, the story centers around one boy's desperate struggle for survival. Lee Ji Hoon is set to play an up-and-coming tough guy within the bullying circle of an elite high school in Busan, who's got a secret in his past and an unexpected charm.

Man-Sik is a single father who raises his 7-years-old daughter Ye-Na alone. He has yet to register her birth, because he wants her birth certificate to be the same as the other kids, which is to have a mother and father. In order to do so, he offers a deal to a woman from Vietnam: he will pay her 20 million won to put her name on a marriage certificate as his wife and Ye-Na's birth certificate as her mother. She declines the offer and Man-Sik becomes devastated. Mi-Hee then appears

Se Jung and Sung Min have, from all appearances, a happy and loving relationship, despite the fact that Sung Min is a cyborg. Se Jung is a scientist by training who met husband Sung Min in graduate school. However, the sudden appearance of former classmate Ji Ah, coupled with Sung Min beginning to remember his past, causes Se Jung to question the decisions that led to her current situation in life.