One day, a third kind of half-men beast "Siuns" appears in the world. Kwak Yun-woo, an ordinary bodyguard, is blackmailed by moneylenders to pay off a family debt. At that moment, Cha Joo-won, a politician known for his campaign for Siuns' rights, enters the scene. Surprised by the congressman's appearance, the moneylenders flee, but why? Kwak Yun-woo is indifferent as he looks at Cha Joo-won. "You'll have to follow me, because I'm carrying your child." What does this mean, how is it possible that Joo-won, who doesn't seem to know Yoon-woo, is carrying his son?