The Good Liar

On the evening of a gala at the Royal College of Forensic Scientists in London's Regent's Park, Professor Claudia Atkins O'Sheil, a forensic scientist, descends the back stairs with Lord Philip Ardmore, the College's president. Philip expects her to deliver a triumphant speech about the Chester Terrace double murder case. But Claudia has prepared a different speech, one that will expose the truth and destroy both their careers. She has hidden her sons somewhere safe, handwritten the speech to avoid digital traces, and burned every draft. The narrative flashes back one year.

Claudia attends the opening party for the College building, still numb four months after the sudden death of her husband, James Atkins, a corporate lawyer who left her deeply in debt. Her boss, Philip, who runs a forensic analysis company called ForSci Ltd, has rapidly promoted her and helped monetize her seminal achievement: the Blood Spatter Probability Scale (BSPS), a program that reconstructs crime scenes from blood spatter data. Philip offers Claudia the clinical directorship, with a pay raise and a house in Belgravia.

Their evening shatters when Maura Langston, head of the Metropolitan Police, summons Philip to Chester Terrace, where two people have been murdered. The victims are Philip's childhood friend Jonathon "Jonty" Stewart and his fiancée, Francesca Emmanuel. At the scene, Claudia views photographs showing stab wounds and post-mortem genital mutilation of Jonty. The attacker entered without forced entry, shot Jonty's guard dog, chased the couple upstairs, killed them with a carving knife, and escaped across the roof.

Jonty's estranged son, Viscount William Stewart, arrives intoxicated but clean of blood, with a fresh Gordian knot tattoo over old self-harm scars. Claudia warns him to get a lawyer. Charlie Taunton, a roguish defense attorney and old friend of James's, arrives as William's counsel. Charlie and Philip share open hostility rooted in their time at Fairchurch, a prestigious boarding school. A text from Langston confirms William has an alibi: time-stamped doorbell footage from Cheyne Walk, the home of Philip's ex-wife Mary Dibden. Claudia accepts the directorship. At home in her cramped Lambeth flat, she shares the night's events with her sister Gina, a former art therapist who has an addiction and moved in to care for Claudia's teenage sons, Sam and Bernie.

Weeks later, Claudia receives the commission for the forensic report on William. His DNA appears only on the gun as a topical shed, meaning skin cells transferred by touch rather than blood, suggesting it was planted. Partial DNA matches to Mary Dibden throughout the house are inconclusive. Running the crime scene video through the BSPS, Claudia notices the attacker has unusually small feet. She then examines the alibi footage and catches a critical discrepancy: William's tattoo shows no scabbing, though it was scabbed when she saw him that night, and a background figure is a schoolboy heading to school, not someone out at night. The time stamp is 12 hours off. William has no alibi.

Charlie asks Claudia about James's last case: the defense of a company owned through shell entities leading to Tontine, a Cayman Islands company. James had been trying to identify the beneficial owner, the person who actually receives the profits. Charlie suggests James's paranoia and his specific objection to Claudia working at ForSci may have been rational responses to discovering something dangerous about the company's ownership.

At the Old Bailey, Dr. Kirsty Parry, a forensic scientist working for rival firm Hamilton Analytics, testifies against the BSPS. Her courtroom manner is poor and the jury dismisses her, but her science is sound: Key variables are outdated, and if the height calculation is corrected, the attacker could be up to a foot shorter than the six-foot-four William. A knife bearing both victims' blood is found at Cheyne Walk with its handle wiped clean, suggesting a setup. William is charged. Meanwhile, Philip arranges Fairchurch places for Claudia's sons, a board membership, and a lectureship, binding her ever deeper to him.

At a lunch hosted by Elena Emmanuel, Francesca's grieving mother, Claudia encounters Mary Dibden and Mary's daughter Amelia Dibden. She registers that partial DNA matches to Mary could also match a biological relative like Amelia. Charlie Taunton is then found dead in his Ferrari at Horsenden Hill, submerged in water on the same road where James died eight months earlier in identical circumstances. Claudia's understanding shifts: James did not kill himself. He was murdered, and so was Charlie.

At a London gallery, Claudia discovers three abstract paintings by Amelia titled Seven Fifty One, Seven Fifty Two, and Seven Fifty Three, the times the murders occurred. From a distance, the pointillist compositions resolve into the blood spatter patterns from each killing. Amelia saw these patterns in person. She was there.

William pleads guilty, receiving two concurrent life sentences. Larry Beecham, William's King's Counsel and Amelia's fiancé, lets the plea stand, and Claudia's 92 percent BSPS result is the decisive evidence. George Farrell, the scene-of-crime manager, reveals that neighbors' cameras captured someone resembling Amelia exiting a nearby house as police arrived, footage that should have been disclosed to the defense but may never have reached Larry. George warns Claudia that with a guilty plea on record, evidence is irrelevant.

After Charlie's funeral, where a celebrant reveals Charlie was the scholarship boy who courageously sued Fairchurch's sexually predatory schoolmasters, Amelia rides in a car with Claudia. When conversation turns to Jonty's parties in Cannes, Amelia calmly releases the driver's seatbelt and yanks the steering wheel, sending the car swerving across the motorway. Claudia recognizes this as the method used to kill James and Charlie.

In prison, William reveals the motive: Jonty raped Amelia when she was 13 during a summer in Cannes. A search of Companies House, the UK government company registry, confirms ForSci's initial funding came from the same shell company chain James was investigating. Claudia learns Philip has inherited the Earldom of Strathearn: With William convicted under the Law of Forfeiture, which prevents someone from inheriting the estate of a person they are convicted of killing, Jonty's entire fortune passes to Philip. Sir Evan Evans, an acquaintance Claudia has long avoided, shows her a photograph from the Albemarle Club's visitors' book proving James met Philip on the day he died. The admissions officer at Fairchurch informs Claudia that a girl has accused Sam of assault, a charge quietly hushed up, giving Philip leverage over her.

Backstage at the gala, Philip tries to cancel the speech. Claudia tells him she knows everything: He is the beneficial owner of Tontine, and Amelia killed Jonty, Francesca, James, and Charlie. Philip admits that when James threatened to go public, he panicked and called Amelia, who got into James's car and killed him. Claudia tells Philip she has no intention of exposing him, that she has too much to lose. Philip, convinced, hands back her microphone and takes the stage, introducing Claudia with a condescending preamble emphasizing her difficult personal circumstances.

Claudia steps to the podium. Her microphone is off. She fumbles with it while the audience shifts uncomfortably. When the lights dim, she spots Gina in the front row, having come despite their estrangement in response to a postcard Claudia sent. Claudia tells the audience the BSPS is fundamentally flawed, William Stewart is innocent, Kirsty Parry was right and was punished for it, and Charlie Taunton was murdered for knowing the truth. She promises to reveal who really killed Jonty and Francesca. And then she does.