Crimson Peak Buffalo, New York 1887. American Heiress Edith Cushing, the daughter of a wealthy businessman Carter Cushing. In the night, young Edith is visited by her deceased mother’s ghost, a black and disfigured figure who warns her “Beware of Crimson Peak.”
Edith currently a budding writer meets Sir Thomas Sharpe in 1901. Sharpe is an English baronet as is his sister Lucille. He is looking for investors to fund his invention of a digging machine that he hopes will revive the clay mines on his family’s estate. Sharpe’s idea and his inability when it came to raising capital earlier have left Mr. Cushing unimpressed and he is averse to the idea. Nevertheless, Thomas charms an initially difficult Edith and they become romantically attached. Thomas demands that Lucille gift him her ring. It is a family heirloom, which she passes over, stating that she hopes it will be returned to her.
Cushing isn’t a fan of Sharpes and employs Mr. Holly as a private investigator. Holly discovers some shocking facts regarding the siblings. They are then pressured by Mr. Cushing to leave America. He also insists that Thomas “break Edith’s heart” and prompts Thomas to criticize Edith’s novel. Thomas returned Edith’s novel the next day with a letter explaining what he had done. Edith accepts Thomas’s offer and the couple reunite. On the same day that day, Thomas. Cushing is brutally murdered at his club. Edith’s former friend Dr. Alan McMichael, is skeptical of the circumstances however, Edith refuses to let him look into the matter. Crimson Peak HD
After the funeral Edith and Thomas marry and depart after the funeral to go to England. They land at Allerdale Hall in Cumberland. The Sharpes’ crumbling mansion is slowly sinking into the Red Clay mine it is on top of. It is also constantly being destroyed by the elements. Lucille is cold with Edith while Thomas remains physically aloof and their relationship is not a thing to be savored. Lucille sips tea made from “firethornberries” with a passion and Thomas convinces Edith to buy the first part of her father’s estate, so he can continue to build his miner. The winter months are approaching and Thomas says the estate is referred to as “Crimson Peak” because of the warm red clay seeping into the snow. The siblings discuss how their father was brutal and robbed the family fortune, and their mother was distant and harsh.
Edith starts to cough up blood and gets weaker. Edith is plagued by terrifying nightmares. She is able to see glowing, skeletal ghosts in Allerdale. They tricked her into entering a closet where she found wax Phonograph Cylinders. She chased her down to the cellars, where she found an unlocked trunk with “Enola” on it.
Thomas takes Edith on an outing to the post office in town, which is where the clerk of the post office gives her a letter from Italy addressed to E. Sharpe. Thomas and Edith stay the night in snow and finally fall in love. Lucille is furious at Edith for not sleeping with Thomas upon their return.
Lucille’s keys are inscribed “Enola”, and Edith takes it when Lucille gets distracted. She uses it to unlock the trunk of the cellar. Edith also finds the gramophone she can utilize to play the wax cylinders inside the closet. Between them and the letter from the post office, she discovers that Thomas was previously married to three wealthy women. One of them was an Italian known as Enola Sciotti. Edith discovers that Lucille is poisoning Edith and that her siblings are engaging in “marriage-and-murder” plans to help their own interests as well as fund Thomas his inventions. Edith confronts her husband and sister in law, however Lucille has them in a passionate embrace. Lucille presses Edith from a balcony in an attempt to end her life however she breaks her leg.
Meanwhile, back in the United States, Alan has learned the information the Mr. Cushing uncovered about the Sharpes before his death Thomas’s many marriages as well as Lucille’s stay in a mental facility. To keep Edith and her family, Alan goes to Allerdale Hall during winter. Alan arrives and finds Edith hurt. Lucille, however, refuses to let him take Edith back to the village. At this point, Thomas has fallen in love with Edith and is suffocated by Lucille and wishes to divorce her. Lucille is then seen slashing Alan underarm and demands Thomas be able to finish the job. To protect Edith, Thomas inflicts an accidental, but not fatal stabbing wound to the stomach of Alan. He then conceals him. Lucille makes Edith sign an instrument of transfer giving the Sharpes complete ownership of the estate. Edith also confesses to having killed Thomas wives. She also confesses that she had a child with Thomas, but it died soon after its birth. Edith’s father was also killed by her, and Edith’s mother was also found engaged in sexual relations with Thomas. Enraged, Edith stabs Lucille with her pen and tries to flee. Thomas burns down the transfer and asks Edith to go with Thomas, in order to start a new life. But, Lucille realizes he wants Edith with them as well. In a jealousy-driven way she kills him using an axe and chases Edith. Aided by Thomas’ ghost serving as a distraction, Edith killed Lucille by using the help of a shovel. Edith is silently wishing Thomas farewell before he vanishes.
Edith and Alan are saved by villagers. Lucille is made the black ghost of Allerdale Hall and can stay in the mansion to play her piano until the end of time. The credits at the end suggest that Edith has written a book titled Crimson Peak, inspired by her own experiences.