A burned-out professional sniper finds himself trapped in an all-glass penthouse by a lethal competitor and must find a way to survive and escape with little to no cover between him and the killer.
While observing their prominent target on a rooftop, sniper Sam and spotter Ken are debating God. Sam catches the ideal shot, but it strikes the target's girlfriend. He kills the target with a second bullet. They both get out of there and go home. Ken continues to ignore Sam's remorse for killing that defenseless girl because he believes they are good government soldiers.
Sam makes the decision to retire and discusses it with Tamara, his boss. Sam agrees when she persuades him to accept one final assignment in Frankfurt. Sam and Ken arrive in Frankfurt, but Ken is unhappy about having to retire. As a farewell present for Sam, they enter an opulent penthouse that was upgraded from Tamara herself, leaving Ken in shock. Sam requests that the manager draw the curtain since he feels uneasy. The boss presents them with two massage girls, Mona and Lily.
Sam and Ken's palms are read by Mona, a fortune teller. Sam yells for the curtains to close as the manager reappears with food, but he sees a flash of sniper glass on a building across from him. When he yells for everyone to crouch, a sniper opens fire. When he attempts to draw the curtains, the manager, a skilled ninja assassin, stops him and attempts to murder him. He is knocked down along with another assassin by Sam. Utilizing Lily's phone, Ken calls Tamara and requests backup. When the assassin regains consciousness, Ken flings him out of the window, but the sniper shoots him, causing him to fall as he bleeds out.
Tamara is attempting to murder them because she dislikes the thought of Sam retiring and believes he will turn against them at some point. To get rid of him in a messy way, Sam murders every assassin and sniper Tamara sent. Lily is killed during the tumultuous altercation, and Tamara keeps making fun of him until Sam discovers how she was watching them. Despite the slim odds of survival, Sam and Mona manage to stay alive after reinforcements arrive by using his rifle and a number of other strategies. Mona sacrifices herself as Sam kills the main sniper and demands that he look after her 8-year-old daughter. When Ken wakes up abruptly, he realizes he is on borrowed time and makes Sam save himself. As Sam destroys a drone that Tamara sent, Ken uses his remaining strength to assist Sam before he passes out from his wound. Sam uses an old tactic from their history to get out of the attack and swears retribution against Tamara while giving thanks to God for keeping him alive.
Later, as she waits in the airport for her flight to Dubai, he calls Tamara. After they start making fun of one another, Sam explains karmic retribution to her, to which she cynically laughs. Sam kills Mona in the bathroom with her daughter's assistance and then casually leaves with the child, hoping that his path to redemption is in capable hands.
