Genetic researcher So-jin, is obsessed with the belief that genes hold a secret: DNA predestines and designs a person’s life, and there must be a way to find a person’s “true love” through DNA. On Christmas eve, So-jin, gets dumped by her boyfriend, and in grief and rage and also drunk, she accidentally sprays hair growth serum on a stranger, Yeon-Woo. After the encounter, Yeon-Woo’s life starts to fumble and the initial hatred slowly turns into something more like, love.