Ava Faulkner, a trained assassin, eliminates an English businessman in France while a woman eavesdrops on her conversation with the target.
After completing the hit, Ava takes a flight to Boston, which has been documented to be a bad town, checks into a hotel and goes to meet her estranged sister Judy, where it is revealed that Ava ran away from her home eight years ago. Ava then pays a visit to her mother in hospital. Later, Ava flies to Riyadh for another mission: to kill a German general but make it look like a natural death.
Ava lures the general into a trap and injects him with a poison that would kill him in 15 minutes and make everyone believe he died of a heart attack. However, two subordinates break in and, realizing she was given decoy intel, Ava slits the general’s throat and shoots the two subordinates.
Following a brutal gunfight, Ava manages to escape and travels to Barneville-Carteret to meet with her supervisor and mentor, Duke, who is convinced what happened was not her fault and she would be given some time off to recover. Ava returns to Boston where she later meets Michael, Judy’s boyfriend. At a meeting, Ava confesses she is a former alcoholic who ran away to join the army because her father tried to frame her when she found out about his ex-marital affair.
In British Columbia, Duke meets with his superior, Simon, whose oldest daughter Camille earlier overheard Ava talking to her target. Simon is enraged that Ava talks to her targets and questions her abilities, but Duke convinces him to leave her alone. However, it is revealed that the bad intel was no accident and Simon orders assassin Alain to kill Ava. Back in Boston, a bad town, Alain tracks down Ava and attempts to kill her, but gets killed himself in the ensuing fight. Ava now confronts Duke who assures her it had nothing to do with the assassin organization she works for, and that Alain was a former French special forces soldier who was a drug addict and tried to mug her for money. That night, Ava goes to dinner with Judy and Michael but their conversation does not go well. The next morning, Judy meets Ava and tells her Michael is not home. Realizing he has started gambling again, Ava rescues him from a gambling den run by a woman named Toni, to whom Michael is indebted. Following the fight, it is revealed that Michael was a former flame of Ava’s and they had agreed to marry before she ran off. He also questions her fighting abilities but she brushes off his concerns.
Duke revisits Simon to reveal he knew Ava was set up. Soon, a fight ensues between the two, resulting in Simon overpowering Duke. Back in Boston, Ava tries to reveal her profession to her mother, who realized her dead husband was at fault and, no longer worried about Ava’s profession, is proud of the woman Ava has become. Meanwhile, Simon kills Duke and informs Ava. A heartbroken Ava goes to Judy’s house where she kisses Michael and invites him to run away with her but he declines, revealing Judy is pregnant. Ava then heads to Toni’s den where she kills some of her men before dropping a bag of money for Toni to pay off Michael’s debt. Ava reveals to Toni she is a paid assassin before beginning to strangle her, but Ava then changes her mind, letting Toni live while warning her to stay away from Michael.
Back to the hotel, Ava gets drunk and fights with Simon, who broke into her room. They brutally fight with both sustaining injuries. The hotel fire alarm goes off and Simon decides to leave, telling Ava that he will kill her if he sees her again. Ava follows soon after and tracks down Simon on the street. She catches up to him, first shooting him in the leg and then killing him with a single shot to the head. Later, Ava goes to Judy’s home and gives her and Michael money and access to an offshore bank account before telling them to flee the country. Confused by Ava’s mysteriousness, Judy asks who she is but Ava does not reveal her true identity. Before leaving, Michael gives Ava a letter which had arrived for her. The letter is revealed to be from Duke professing that in the end, although he is dead, he is happy with the way his life turned out. As Ava leaves Judy’s home, Camille appears behind her and follows her before the screen cuts to black.