Won Ryu-Hwan (Kim Soo-Hyun) trained in the North Korean Special Forces. He can speak five languages and is also a lethal killing machine. Two years ago, he received orders to deploy to South Korea as a spy. While wondering in a poor neighborhood in Seoul, Won Ryu-Hwan passed out and was awakened by a worried old mother. The woman then allowed him to live in a small apartment above her modest convenient store and let him work in her store.