The film revolves around a professional hitman (Jang Dong-gun) who is conflicted about killing his last target (Kim Min-hee).

Gon is to go to South Korea to tie up the loose end - the little girl's mother Choi Mo-gyeong, a risk manager at an investment firm.

As he studies Mo-gyeong's routine, he learns of her visits to her senile mother in a hospital and watches as she mourns her daughter.

Prior to his assassination, Yun-guk had gained access to John Lee's accounts for money laundering and had begun trying to sell them to the Russian Mob.

However a Chinese-American street assassin under Dai Ban, named Asing, is sent to eliminate her after he successfully murders the other two "loose ends".

As Gon still hasn't completed his assignment, Dai-Ban sends Chaoz, Juan, and Alvaro to South Korea to find him.

Chaoz meets a black market American arms dealer in Seoul and quickly kills him and the bodyguard to avoid paying for the firearms.

Gon creates a distraction, knocking down Alvaro and engaging in a firefight with both Chaoz and Juan, allowing Mo-gyeong to escape.

After a conversation with Chaoz, Gon tells Mo-gyeong she needs to shoot the next person who enters from the lift because it is her daughter's murderer.

A flashback shows Gon's mother, who abandoned him in the states and killed herself early on in the film, telling him not to cry as they would have a good life once they move to America.

Writer-director Lee Jeong-beom interviewed special forces troops in South Korea and the United States to learn their reality and incorporate it into his screenplay.

Despite its star director and actor, the film underperformed at the box office against Hollywood blockbusters X-Men: Days of Future Past and Edge of Tomorrow.