Wealthy crime novelist Harlan Thrombey (Christopher Plummer) invites his family to his mansion for his 85th birthday party. The next morning, Harlan's housekeeper Fran (Edi Patterson) finds him dead, apparently having slit his own throat. An anonymous party pays private detective Benoit Blanc (Daniel Craig) to investigate.Blanc learns that Harlan had alienated much of his family: he had threatened to expose his son-in-law Richard (Don Johnson) (Harlan's son-in-law and Linda's husband, who helps run his wife's company) for having an affair; cut off his daughter-in-law Joni's (Toni Collette) (widow of Harlan's deceased son Neil, who is a lifestyle guru and influencing person) allowance for stealing money meant for her daughter's tuition; fired his youngest son Walt (Michael Shannon) (Harlan's youngest son, Donna's husband, and the CEO of his father's publishing company) from his publishing company; and cut his lazy grandson Ransom (Chris Evans) (Harlan's grandson, Linda and Richard's son, and a spoiled playboy) out of his will.
Nobody in the family respects Walt, although he is proud to call himself a "self-made man".Linda Drysdale (Jamie Lee Curtis) (Harlan's eldest daughter and Richard's wife. She is a real estate mogul who runs her own company with her husband's support). Megan "Meg" Thrombey (Katherine Langford) (Harlan's granddaughter, Joni and Neil's daughter, who studies at a prestigious liberal arts college). Jacob Thrombey (Jaeden Martell) (Harlan's grandson, Walt and Donna's son, who holds alt-right views and is always on his phone). Donna Thrombey (Riki Lindhome) (Harlan's daughter-in-law and Walt's wife). Wanetta "Great Nana" Thrombey (K Callan) (Harlan's elderly mother)Detective Lieutenant Elliot (Lakeith Stanfield) (a local detective involved in the investigation) & Trooper Wagner (Noah Segan) (a police officer involved with the investigation) are conducting the initial investigation and the family is upset as it is a suicide case.Unknown to Blanc, after the party Harlan's nurse Marta Cabrera (Ana De Armas) (Harlan's nurse and caretaker who had a close relationship with him), giving Harlan his daily medications, had a fatal mix-up between similar-looking bottles of Ketorolac and morphine. Recognizing that he was likely minutes from death from an overdose, Harlan told Marta how to avoid suspicion by making it appear he was still alive after she had driven home, and then slit his own throat to save her from any suspicion.Basically, Harlan asked Marta to leave publicly and then come back through climbing a side pipe. Then he made her dress like himself and go downstairs where Walter saw her and acknowledged her as Harlan. She then goes back up and leaves through the same pipe route that she came in. Carrying out Harlan's instructions, Marta was seen escaping the house by Harlan's very elderly mother, who mistook her for Ransom.Marta cannot lie without vomiting, so she gives technically true but incomplete answers when Blanc questions her. Blanc asks her to assist in his investigation. As they search the property, Marta attempts to conceal evidence (She uses a magnet to erase the security tapes, she steps over her foot-marks in the mud from where she re-entered the house at night). The family is shocked to learn from Harlan's lawyer that Harlan left everything to Marta. They turn on her, but Ransom helps her escape. At a restaurant, Ransom tricks Marta into confessing to him, and offers to help her in exchange for his share of the inheritance. The other Thrombeys realize that, under the slayer rule, Marta will lose the inheritance if she is found guilty of killing Harlan, but Blanc tells them that they all are still suspects. They try to persuade Marta to renounce her inheritance.Marta receives a blackmail note with a partial photocopy of Harlan's toxicology report. She and Ransom drive to the medical examiner's office, but it has been destroyed in a fire. Marta receives an email with a time and address to meet the blackmailer. When Blanc spots her and Ransom, Marta speeds away. The police catch them and arrest Ransom. Blanc explains to Marta that Harlan's mother had seen Ransom climbing down from Harlan's upstairs rooms on the night of his death.Marta goes to the address in the email and discovers Fran drugged. She performs CPR and calls 911. Marta confesses everything to Blanc, but Ransom has already informed on her. At the house, Marta finds a copy of the full toxicology report hidden in Fran's cannabis stash. Marta is about to confess to the family, but Blanc interrupts her after reading the report. He brings Marta, Ransom and the police to a room to reveal his deduction.After Ransom learned at the party that Harlan was leaving everything to Marta, he swapped the contents of Marta's medication vials so she would kill Harlan with an overdose of morphine, making her ineligible to claim his inheritance. However, Marta, an experienced nurse, administered the correct medicine without reading the labels, and is thus innocent of Harlan's death. After the death was reported as suicide, Ransom anonymously hired Blanc to discover Marta's guilt. Fran later saw Ransom swapping the vials back and sent him the blackmail note. Realizing that Marta had given Harlan the correct medication, Ransom passed on the blackmail note to Marta, removing the address and time. He destroyed the evidence of Marta's innocence by burning down the medical examiner's office and burning Fran's copy of the toxicology report. He drugged Fran with morphine and emailed her location to Marta, planning to frame Marta for Fran's murder.Marta receives a call from the hospital and says that Fran is alive. Believing that Fran will implicate him, Ransom angrily confesses and vows revenge. However, Marta vomits on Ransom; she lied that Fran had survived in order to trick Ransom into confessing. He attacks her with a knife, but discovers it is a retractable stage knife. As Ransom is taken into custody, Marta watches the Thrombeys from what is now her mansion.
Storyline
When renowned crime novelist Harlan Thrombey (Christopher Plummer) is found dead at his estate just after his 85th birthday, the inquisitive and debonair Detective Benoit Blanc (Daniel Craig) is mysteriously enlisted to investigate. From Harlan's disfunctional family to his devoted staff, Blanc sifts through a web of red herrings and self-serving lies to uncover the truth behind Harlan's untimely death. — Lionsgate Nothing could blemish the lavish birthday party at the palatial estate of acclaimed crime/mystery novelist Harlan Thrombey except for his strange and unaccountable death. Now, the sharp knife in the silver-haired deceased's hand is a dead giveaway that something, or someone, had been bothering Harlan. But cryptic detective Benoit Blanc is not entirely sure. Because, as it turns out, there are more than a few members of the successful author's clingy family who have been economical with the truth so far. And as Blanc struggles to shed light on a tangled mess of half-baked leads and little white lies, all eyes are on the grand prize: Harlan's magnificent legacy. The question is, can Benoit find the answer to this perplexing case before someone else dies? — Nick Riganas The morning after his eighty-fifth birthday party held at his Norfolk County mansion with his dysfunctional family of his mother, his surviving children, their spouses, and their children in attendance, successful novelist and publishing house owner Harlan Thrombey, self-made in his wealth, is discovered in his attic study by Fran, one of the housekeepers, him dead with his throat slashed, knife in hand. Arguably the last person to see him alive was his Brazilian nurse, Marta Cabrera, the daughter of an illegal immigrant, something she has told few within this sphere. She went through her evening ritual of playing a game of Go with him and administering his medication at that time. A week later following the funeral, the local police are questioning the family members at the mansion to see what happened that night that could have led to his death, the questioning in their belief that Harlan committed suicide. The interviewees all confirm the time-line of events supporting that suicide belief. One other person at each of the interviews is famed private detective Benoit Blanc, who the family will learn has been retained as a consultant. What he fails to tell them in return is that he was hired anonymously, cash in advance. Blanc is able to bait many of the interviewees into bad mouthing other family members while being reticent to admit something that Blanc already seems to know about them, each of the family members looking out solely for him/herself. The key interview, one that happens unexpectedly, may be with Marta, who Blanc suspects was Harlan's confidante and who cannot lie in always having the physical reaction of vomiting whenever she does. One person not interviewed in being absent is one of Harlan's grandchildren, overly privileged Ransom Drysdale, who left the party early after having had a private conversation with his grandfather, he not being interviewed somewhat immaterial as Ransom was known to have not been at the mansion at the time of death. The nature of the investigation changes a week later at the reading of the will, where all will discover but some who were already aware that Harlan had rewritten it the week before his death, the specific changes not known until this day. With all these comings and goings, learning the full truth of what happened with Harlan may come down to discovering the unknown of who hired Blanc and why. — Huggo