HONG Gildong is an infallible private detective with an exceptional memory and quirky personality. While chasing the only target he failed to find, he gets entangled in a much bigger conspiracy than he bargained for.

Set in a village right after the Korean War, poor but good-hearted Heo Sam-gwan sets out to win the most beautiful girl in the village, Heo Ok-ran, by selling his blood to earn money. Years later, the two are happily married with three children, but their family undergoes a crisis when Sam-gwan’s eldest son doesn’t resemble him and rumors spread about the boy’s paternity.