Moon Joo is a diplomat and a former ambassador to the United States. She has built great trust in the international community through her insightful judgment and actions. She learns that there was political maneuvering behind an assassination case involving South and North Korea. Meanwhile, San Ho is an elite mercenary. He is a mysterious figure whose nationality and past are both shrouded in secrecy. Moon Joo and San Ho together pursue the truth behind the major incident.(Source: AsianWiki)