as Song Min-gyu Captain Song Min-gyu is Hwasaeng Defense Command's best elite officer with full specs. He was scheduled to be appointed as an operation officer at the headquarters of the Army after passing the rank of major with the highest rating, but becoming a military prosecutor suspect who is caught in an unsavory case and undergoes military trial. On the way of life and death, Song is selected as the leader of the North Star and gets the last chance. To get out of the crisis, he must succeed in this operation, but he has another reason to return to the demilitarized zone. Lee Hyun-wook as Lee Joon-sung First Lieutenant Lee Joon-sung is affiliated with a commando regiment that conducts special warfare directly under the command corps. While attending university, he was transferred to the military academy and received the Presidential Award. A case breaks out in the DMZ, and he is selected as the deputy team leader of the special mission team. He unites the special lease into one with his unique gentle leadership, but engages in a subtle nervous war with Captain Song, who focuses only on the success of the operation. Supporting Special Polaris Mission Unit Lee Ha-yul as Park Ki-hyung Sergeant First Class Park Ki-hyung is an active duty sergeant who has is the third generation soldier in his family. He was supposed to get married but was assigned to the operation in the DMZ as a sniper. Choi Yoon-je as Staff Sergeant Ju Moon-chul 1997 Operation of the DMZ Yoo Sung-joo as Lee Hyuk Chairman of the National Defense Commission and National Assemblyman. He is running for the presidential elections. Choi Deok-moon as Han Dae-sik Han Dae-sik is the Commander of the Armed Forces of the Ministry of Defense of the Republic of Korea. He has risen to the present position by surviving a gunfight with the North Korean military in the DMZ in 1997, but suffers from post-traumatic stress disorder due to the shock of that accident. When a situation arises in the DMZ, he instructs Captain Song on a secret mission. Yeon Woo-jin as Captain Jo Min-gook Commander of the 1997 Search Operation in the DMZ. Chengong-ri village people Lee Soon-won as Chun Min-jae, Da-jeong's husband and Su-yeong's father. Park Da-yeon as Chun Su-yeong, Da-jeong and Min-jae's 10-year-old daughter. A cheerful girl who is good at running and likes Sergeant Yong Dong-jin