British newlywed Regina Lambert (Thandiwe Newton) finds herself in the lively streets of Paris, blissfully married to her husband Charlie (Stephen Dillane), until a short holiday with her friend Sylvia (Sakina Jaffrey) propels her into a whirlwind of chaos. Returning home, she is determined to end her marriage, but instead, she stumbles upon a ghastly reality: their apartment has been stripped clean, and her husband has been brutally murdered. In the midst of this overwhelming grief, Commandant Dominique (Christine Boisson) and Lieutenant Dessalines (Simon Abkarian) are already on the scene, piecing together the mystery.

Dominique informs Regina that Charlie’s lifeless body was found near the train tracks just outside Paris. Although Regina knew Charlie as an art dealer with Swiss roots, the shocking discovery of multiple passports bearing different names throws her into confusion. It turns out that Charlie sold all their belongings at three separate auction houses, pocketing an astounding $1.8 million, which is now mysteriously missing. As Regina grapples with her loss, she becomes a target, pursued by a trio of ominous figures: Lee Il-Sang (Park Joong-Hoon), Lola Jansco (Lisa Gay Hamilton), and Emil Zadapec (Ted Levine), each with their own agenda tied to her husband’s covert life.

Amid the turmoil, Regina is unexpectedly reunited with the enigmatic Lewis Bartholomew (known to her as Joshua Peters) (Mark Wahlberg), a stranger she met during her vacation. Their paths cross when Joshua offers her a lift home from the airport and later finds her in distress. He helps check her into a hotel just as Dominique begins to shadow their every move. Subsequently, Regina is contacted by Carson J. Dyle (Tim Robbins), who claims to be Lewis Bartholomew and asserts that he represents the US government. With a haunting intensity, he reveals that Charlie had a hand in facilitating a defense project between the US and UK, showing her a photograph that links Charlie to Lee, Lola, and Emil from a pivotal mission three years prior, known as Operation Verify.

As the layers of deception peel back, the stakes escalate. Carson discloses that the mission hinged on 46 diamonds valued at $6 million, which Charlie allegedly absconded with after a catastrophic ambush that left him and his accomplices marred by betrayal. Lola’s cryptic warning in a chance encounter at a flea market reinforces the dire implications of her husband’s actions. As Regina navigates this labyrinth of secrets, she finds herself in perilous situations, including a harrowing attack by Emil that Joshua manages to thwart. Yet, trust becomes a frail commodity as questions about Joshua’s true loyalty surface.

As Regina unwittingly becomes embroiled in the tumultuous legacy of her husband, she unravels a tapestry of alliances and treachery. The stakes rise further when she learns that the trio is not merely pursuing her but is also on the hunt for the hidden diamonds. An unexpected betrayal unfolds, thrusting Regina into a vortex of danger as she grapples with the revelation that Joshua is, in fact, Alexander Dyle, Carson’s brother, who was presumed dead in the ambush. An attempt to flee Paris leads her straight back to peril as the remnants of Charlie’s life haunt her at every turn.

In the throes of this tense and gripping narrative, the balance of power shifts dramatically. Regina uncovers the sinister truth that Carson, concealed in layers of deception, is indeed the mastermind behind the series of events leading back to Charlie’s murder. As the mystery climaxes, Regina holds the key to the diamonds—a collection of rare stamps that represent the last vestiges of her husband’s underworld dealings.

“Don’t trust him. He’s after the money.” A whispered warning from Lola echoes in Regina’s ears as she fights to disentangle herself from the deadly web surrounding her. The drama culminates in a frantic showdown, where loyalties are tested, and the line between ally and adversary blurs.

Ultimately, Regina’s quest for truth leads to an unexpected resolution, as she discovers that the copies of the diamonds were merely a façade. With all the revelations splintering the relationships she thought she knew, she hands over the true originals to Lewis, declaring that the burnt copies were only meant to remove any temptation of greed. As she tenderly moves forward from the turmoil, she finds solace in the arms of Lewis, embarking on a new chapter amidst the shadows of her past. Meanwhile, Charlie’s enigmatic mother feeds Carson in prison, sealing the tragic fate of their intertwined lives.