See How They Run (2022) Plot Summary & Ending Explained

In the bustling atmosphere of 1953 London, the iconic Agatha Christie play, The Mousetrap, is poised to celebrate its 100th performance. However, the event takes a dark turn when the disreputable American director, Leo Köpernick, is brought on by producer John Woolf to helm the film adaptation. Following a scandalous altercation with the lead actress, Sheila Sim, which culminates in a brawl with her husband, Richard Attenborough, Köpernick is mysteriously murdered backstage by a shadowy figure.

The ensuing investigation is led by the astute Inspector Stoppard, alongside the inexperienced yet eager Constable Stalker. As both delve into the depths of the theatre world, every person within the venue becomes a suspect, including the playwright's keen producer, Petula Spencer, and Edana Romney, Woolf's wife. Stoppard initially considers shutting down the theatre until the mystery is resolved, but his plans are interrupted by Metropolitan Police Commissioner, Harold Scott.

The detective duo searches Köpernick's hotel room at the Savoy, discovering an intriguing address book filled with women's names. The hotel manager recounts a heated dispute between Köpernick and the screenwriter Mervyn Cocker-Norris, who confesses to arguing about Köpernick's vision for an action-packed film ending. Mervyn, residing with his fiery "nephew" Gio, recalls a "plain woman" accompanying Köpernick's son during their stay.

The investigation takes a twist when they question Woolf, who had fallen victim to Köpernick's blackmail after the director learned of Woolf's affair with his assistant, Ann. Meanwhile, an usher named Dennis provides vague information regarding a suspicious figure. As the plot thickens, Spencer reveals that she had secured the film rights for The Mousetrap solely for Woolf, who is bound by contract from producing it until the play concludes.

During an evening at a pub, Stoppard candidly discusses his past with Stalker, disclosing that his wife left him after having a child with another man. This revelation leads to unexpected connections when Stalker uncovers a photograph of Stoppard's ex-wife, lining up with Mervyn's earlier description. This tantalizing clue casts suspicion on Stoppard, prompting Stalker to comb through Köpernick's address book for further leads.

As the investigation unfolds, Stoppard and Stalker attend a performance of The Mousetrap. During this tense moment, Mervyn, Woolf, Dennis, Gio, and Stoppard exit the auditorium, with Stalker following closely behind as she witnesses Stoppard retrieving his gloves. In a tragic turn of events, Mervyn is brutally murdered by an unidentified assailant. Stalker misinterprets the scene, knocking Stoppard unconscious in her haste to apprehend what she believes to be the murderer.

Regaining consciousness in a holding cell, Stoppard is shocked to find himself accused of the murders by Stalker and Scott. In a twist of fate, Stalker locates Joyce, the mother of Köpernick's son, who ultimately confirms that she is not Stoppard's ex-wife, clearing his name. As the investigation further escalates, Joyce reveals overhearing someone speaking with a peculiar "village idiot" accent, which becomes an essential clue.

Through painstaking examination of Mervyn's research regarding The Mousetrap, Stoppard ultimately deduces the identity of the real killer and races to the suspect's location just as Stalker discovers critical evidence pointing to Dennis's guilt.

In a climactic confrontation at Agatha Christie's residence in Wallingford, Berkshire, Stoppard, Sim, Woolf, Ann, Spencer, and her mother find themselves held at gunpoint by Dennis, who possesses a chilling backstory linked to the tragic inspiration for the play. In an explosive finale, the stage transforms into a battleground, complete with deception and a showdown involving a poisoned cup, mistaken identities, and life-threatening heroics.

Through the chaos, Stalker displays her bravery as she risks her life in the name of justice, while Stoppard bravely confronts the threats posed by Dennis, ultimately leading to a resolution that sees him injured but triumphant. As time passes, Stalker triumphs in her sergeant's exams, while Stoppard receives the esteemed King's Police and Fire Services Medal. They rekindle their bond by attending another performance of The Mousetrap, illustrating the persistence of resilience in the face of darkness.

The ending of "See How They Run" reveals that the true culprit behind Kopernick's and Mervyn's murders is Dennis, the usher who had a deep personal connection to the story that inspired "The Mousetrap." Dennis had lost his brother in a real tragedy and believed the play, which was based on his life, was exploitative and mocking his pain. His anger grew over the years as he watched the story being turned into a theatrical and cinematic spectacle, feeling that his grief was being profited from and trivialized. When Kopernick, the film director, began creating a climax that mirrored the original story of Dennis’ life but with added violence, Dennis saw it as a final insult and decided to take revenge. He murdered Kopernick and later Mervyn, who shared ideas with Kopernick and was involved in the film’s development.

However, the chaos reached its peak when Agatha Christie herself intervened. She cunningly offered Dennis poisoned tea, trying to calm him down and prevent further violence. Unfortunately, Dennis, in his desperation, seized Christie as a shield and almost caused more destruction. Stoppard and Stalker, the detectives, eventually uncover Dennis’ motive through clues he inadvertently left behind. They learn that Dennis felt betrayed and misunderstood, believing that the art based on his tragedy had been perverted to mock his suffering. Ultimately, Dennis’s rage culminated in a tragic shootout, where he held Christie hostage and was finally shot by Stoppard when he threatened to kill others, including himself. The film ends with Stoppard breaking the fourth wall, telling the audience not to reveal who the killer is, emphasizing the classic whodunit style.