The drama revolves around a guy and a girl, who both experience a painful end to their first loves at the tender age of 15, and then meet again as adults by playing game of love hide and seek. Middle school sweethearts Jung-woo and Soo-yeon were separated in a horrifying tragedy that continues to weigh down on them as adults. Now a guilt-ridden detective, Jung-woo has been desperately searching for Soo-yeon for years, but when he crosses paths with her again, she has already become someone else with a new identity.