Dong-Chul (Don Lee) and Ji-Soo (Song Ji-Hyo) are a happily married couple. One day, Dong-Chul comes home to find his house in disarray and his wife is missing.
An ace crisis negotiator faces off against a cold-blooded hostage taker. Over the course of 21 hours, she attempts to crack his unusually calm demeanor and force him to reveal his motivations.
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.