South Korea's intelligence agency NSSTF-A is a very powerful intelligence team. Captain Zheng Liujian (played by Zhang He) is very capable, but seems to be hiding some secrets; team member Ji Xiuyan (played by Lee Da Hae) has super shooting ability. Although she is often not in good shape on weekdays, she can actively play her role at critical moments. She is an indispensable female team member; and NSS Deputy Director Cui Min is a super-strong background in the US Pentagon. She runs around in negotiation occasions and is the absolute core of the NSS reform team. In order to solve the mystery behind "Baeksan", NSS launched a series of investigations and searches, and the truth of the story is extremely complicated and unexpected. Captain Liujian was also irresistibly involved in these things and changed his life trajectory... This film is a follow-up story of "IRIS". The first part was starred by Lee Byung-hun and Kim Tae-hee as the male and female protagonists respectively.