The K2 (2016)

Kim Je Ha, a former mercenary known as “K2,” becomes a fugitive after being wrongfully accused of killing his girlfriend in Iraq. He returns to Korea and works as a bodyguard for Choi Yoo Jin, the wife of presidential candidate Jang Se Joon. Je Ha plans revenge on Park Kwan Soo, Se Joon's rival, whom he believes ordered his girlfriend's murder. While guarding Go An Na, Se Joon's reclusive daughter, Je Ha and An Na grow close. However, Je Ha's loyalty is tested when he learns that Yoo Jin, his boss and ally in revenge, is the one threatening An Na. (Source: MyDramaList)