Plot

In the aftermath of a family tragedy, an aspiring author is torn between love for her childhood friend and the temptation of a mysterious outsider. Trying to escape the ghosts of her past, she is swept away to a house that breathes, bleeds - and remembers.

Edith Cushing's mother died when she was young but watches over her. Brought up in the Victorian era, she strives to be more than just a woman of marriageable age. She becomes enamored with Thomas Sharpe, a mysterious stranger. After a series of meetings and incidents, she marries Thomas and comes to live with him and his sister, Lady Lucille Sharpe, far away from everything she has known. The naive girl soon comes to realize not everything is as it appears, as ghosts of the past quite literally come out of the woodwork. This movie is more about mystery and suspense than gore.—@Avivafae

Buffalo, New York, 1880s. Edith Cushing (played by Mia Wasikowska) is haunted (in some cases, literally) by the death of her mother - she died when Edith was young. Then, she meets an English entrepreneur, Sir Thomas Sharpe (Tom Hiddleston), the relationship develops, and life seems to be improving. However, her father, Carter Cushing (Jim Beaver), disapproves of Sir Thomas and tries to have Sir Thomas and his scheming sister, Lucille (Jessica Chastain), sent back to England. Mr Cushing then dies in mysterious circumstances, leaving Edith and Sir Thomas free to wed, which they do. The married couple and Lucille move into the Sharpe ancestral home in England, the run-down Allerdale Hall. Hardly has she moved in than Edith's nightmares become quite vividly real, being haunted by ghoulish apparitions. It's as if the house doesn't want her there.—grantss

At the turn of the twentieth century in Buffalo, New York, the aspiring writer Edith Cushing is the daughter of the wealthy entrepreneur Carter Cushing. Edith saw the ghost of her mother that warned her to beware of Crimson Peak when she was a child, and, presently, she is writing a ghost story. Now, she is visiting a publisher that is a friend of her father, and she stumbles upon her childhood friend, the ophthalmologist Dr. Alan McMichael, who has returned from overseas and is opening an office in the same building. Out of the blue, she meets the English baronet Sir Thomas Sharpe, who has come to Buffalo with his sister Lucille Sharpe to seek investors for his machine that operates with clay. He has a meeting with Carter Crushing and other businessmen, but Carter refuses to invest in his invention. During the night, the ghost of Edith's mother visits her and warns Edith again to beware of Crimson Peak. Soon, Thomas seduces Edith, and Carter hires a private detective to investigate the lives of Thomas and Lucille. A couple of days later, the detective brings a report to Carter, disclosing dark secrets from the siblings' past. Carter pays a large amount to Thomas to end his relationship with Edith, but he is brutally murdered. Thomas explains to Edith his attitude, and they get married and travel to England to live in his derelict mansion over a red clay mine at Allerdale Hall with Lucille. Edith starts to see a red ghost and discovers that an Italian woman has sent a letter to him. Then, she becomes weak and coughs blood. What is happening to Edith, and what is the mystery of Allerdale Hall and the siblings Sharpe?—Claudio Carvalho, Rio de Janeiro, Brazil

In Buffalo, New York, 1887, American heiress Edith Cushing, the young daughter of wealthy businessman Carter Cushing, is visited by her recently deceased mother's black, disfigured ghost who warns her, "Beware of Crimson Peak." In 1901, Edith, a budding author, meets Sir Thomas Sharpe, an English baronet who has come to the United States with his sister, Lucille, to seek investors for his clay-mining invention. Unimpressed with Sharpe's previous failures to raise capital, Cushing rejects Thomas's proposal. Edith's mother's spirit once again visits her, bearing the same warning. When Thomas and Edith become romantically involved, both Edith's father and her childhood friend, Dr. Alan McMichael, disapprove. Mr. Cushing hires a private detective, Mr. Holly, who uncovers unsavory facts about the Sharpes..

In 1887 Buffalo, N.Y., Edith Cushing (Mia Wasikowska), the young daughter of wealthy American businessman Carter Cushing (Jim Beaver), is visited by her mother's ghost who warns her, "beware of Crimson Peak." Edith was still just 10 years old, and her mother had died a few years ago by black cholera. Edith did not understand the warning at the time.

Fourteen years later, Edith is now a budding author who prefers penning ghost stories to writing the romance novels that her editor Ogilvie (Jonathan Hyde) wants. Edith is a free spirit and is not afraid to challenge the social conventions of the time. Edith realizes that her feminine handwriting gives her away and decides to type her stories from now on. She meets Sir Thomas Sharpe (Tom Hiddleston), an English baronet who has come to the United States seeking investors, including Edith's father, for his clay-mining invention. Thomas likes Edith's writing and charms his way into her good books. Disdaining privileged aristocracy and unimpressed with Sharpe's prototype and previous failures to raise capital, Cushing rejects Thomas's proposal. Cushing says that he worked as a steel worker on buildings before he owned them, and Thomas never worked a single day in his life. Cushing tells Edith that there is something about Thomas that he doesn't like. Edith notices that Thomas and his sister, Lucille (Jessica Chastain), wear expensive but outdated and somewhat-frayed fashions. Edith notices that Thomas's coat is hand stitched but at least a decade old. Shortly after, Edith once again is visited by her mother's spirit bearing the same warning.

Sir Thomas is determined to persuade Mr. Cushing to change his mind. However, he and Edith become romantically attached. Thomas takes Edith to a ball in front of the entire high society and chooses Edith over Eunice (Emily Coutts), a high society debutante who fancies Thomas. Thomas and Edith perform a Waltz for everyone to see. Edith had never been given so much attention in her life and was never in the spotlight before. It was exhilarating for her.

Cushing and Edith's childhood friend, Dr. Alan McMichael (Charlie Hunnam), disapprove. Cushing was always fond of Alan and had hoped that he and Edith would end up together. Alan is an Ophthalmologist. Alan also asks Edith to be careful with Thomas, but Edith does not look at Alan any more than a good friend. Lucille also questions Thomas's choice and says Edith is just a child. But Thomas takes an engagement ring from Lucille to propose to Edith, promising to return it.

Mr. Cushing hires a private detective Holly (Burn Gorman) who uncovers unsavory facts about the Sharpes. Mr. Cushing confronts the siblings and bribes them into returning to England. As Cushing insisted, Sir Thomas abruptly and cruelly ends his and Edith's relationship (by insulting her writing and calling it immature and childish) at a dinner hosted by Mr Cushing, but the next morning, he sends her a note explaining his actions. Thomas claims that Cushing had told him that he did not have the means to provide for Edith.

Not long after, Mr. Cushing is brutally murdered, though his death is ruled accidental as his body was found in a bathroom and it seemed like he slipped and bashed his own head open upon the bathroom sink. Alan wants to perform an autopsy, but Edith stops Alan as she considers it disrespectful to her father's memory. Edith and Sir Thomas eventually marry and return to Cumberland, England. They arrive at Allerdale Hall, the Sharpes' dilapidated mansion, which sits atop a red clay mine. As Edith settles in, she finds that Lucille acts somewhat cold toward her while Sir Thomas remains physically distant. Edith is left confused and uncertain by their behavior. Edith is not given copy of the house keys and is told never to go below the ground level of the house.

Gruesome ghosts begin appearing to Edith throughout the mansion. To help calm Edith, Sir Thomas takes her into town. After being snowed in for the night, they finally consummate their marriage. Lucille angrily lashes out when they return the next morning, frightening Edith. By the time Sir Thomas mentions that the estate is also referred to as "Crimson Peak," due to the warm red clay seeping up through the snow, Edith is growing increasingly weaker and coughing up blood.

Edith explores the mansion and begins piecing clues together, discovering that Sir Thomas previously married three wealthy women who were fatally poisoned for their inheritances. She realizes she, too, is being poisoned. She also discovers the siblings have had a long-term incestuous relationship, resulting in a sickly infant that died. Lucille murdered their mother after she had discovered her children's incest. Sir Thomas inherited the family manor that, like many aristocratic estates of the era, is no longer profitable; the Sharpes are virtually penniless. The brother and sister began the "marriage and murder" scheme to support themselves and to fund Thomas's inventions.

Back in the United States, the detective that Mr. Cushing had hired tells Alan what he uncovered about the Sharpes, including Thomas's multiple marriages (to Enola Sciotti, Margaret McDermott, and Pamela Upton) and Lucille's time in a mental institution. Realizing Edith is in danger, Alan arrives at Allerdale Hall to rescue her. Lucille stabs him in the left armpit, then demands that Sir Thomas finish him off. Sir Thomas, who has fallen in love with Edith and does not want her harmed, inflicts a second, non-fatal stab wound to Alan before hiding him in the cellar. Lucille forces Edith to sign a transfer deed granting the Sharpes ownership of the Cushing estate and also confesses to her that she was the one who murdered Edith's father. After Edith signs the deed, she stabs Lucille in the chest with a pen and tries to flee. Sir Thomas burns the deed and promises to protect Edith so that she and Alan can escape.

Lucille, jealous over Sir Thomas falling in love with Edith, murders him in a rage. She then pursues Edith. Aided by Sir Thomas' ghost, Edith kills Lucille with a shovel. Sir Thomas bids Edith a silent farewell as his spirit departs. Edith and Alan are rescued, and Lucille's ghost now haunts Allerdale.

The end credits imply that Edith has written a novel titled Crimson Peak based on her experiences.