English Title: Undercover
Chinese Title: 卧底
Cast: Ji Jin-hee, Kim Hyun-joo, Jung Man-sik, Heo Joon-ho
Synopsis: Han Jeong-hyeon (Ji Jin-hee) is an agent of the National Intelligence Service (formerly the Agency for National Security Planning), who has been hiding his identity for the past 30 years as a father and owner of bicycle repairing shop. Choi Yeon-soo (Kim Hyun-joo), his wife and a Human Rights lawyer, becomes the first Director of the Corruption Investigation Office (CIO). These characters are trying to uncover the truth, pitted against a huge force holding a top position. The series tests their relationship as husband and wife when the secret life of Jeong-hyeon comes to light.