In 1987, Im Soo Ho and Eun Young Ro are students at a prestigious university in Seoul. Im Soo Ho, who grew up in Germany, has a gentle charm but gives off an air of secrecy. Eun Young Ro, who is lively, lovable, and cheerful, fell in love with him at first sight at a social gathering. One day, Soo Ho suddenly rushes into a female dormitory covered in blood, and Eun Young Ro hides him and tends to his wounds despite facing danger under close surveillance. Among those monitoring, Soo Ho and Young Ro must avoid Pi Seung Hee, the notoriously strict and imposing housemother of Young Ro's dorm, and Kye Boon Ok, a phone operator at the dorm who had to forgo a college education due to her family's financial circumstances. Lee Kang Moo is the relentless head of Team 1 of the National Intelligence Service (NIS) and always insists on doing everything by the book. By contrast, NIS agent Jang Han Na is impulsive, hot-tempered, and passionate about her job. Kang Chung Ya is a beautiful, talented surgeon at a state-run hospital who can charm anyone in a split second. Although her skills in the operating room have earned her a solid reputation as a dependable surgeon, Dr. Kang is mysterious and appears to be hiding something.