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.

Woo Jin takes care of his son Ji Ho alone after his wife Soo A passed away. Before she passed away, she promised she would be back on a rainy day one year later. One year later, Soo A appears again, but she does not remember anything.