Ralph Fiennes’ sophomore directorial effort, The Invisible Woman, portrays nearly the same amount of cruelty as his debut, Coriolanus. There might not be bloodshed in the telling of the affair Charles Dickens began with a teenager when he was a married, middle-aged man, but the emotional savagery that runs throughout is often just as stomach-churning.

Fiennes plays Dickens, whom we meet when the author has attained rock-star status despite a wife, Catherine (Joanna Scanlan); 10 children; and unfortunate hair. While staging and acting in a work of his playwright friend, he meets 18-year-old Nelly (Felicity Jones), who comes from a family of actors, including her sisters and the Victorian-era equivalent of a stage mom (Kristin Scott Thomas). Nelly’s mother recognizes both her daughter’s questionable future as a thespian as well as the lascivious way in which Dickens drinks her in. So she does what any mum who wants the best for her daughter would do: arrange for her virtuous youngest child to become the lifelong secret lover of a wedded 45-year-old.

Adapted by Abi Morgan (Shame, The Iron Lady) from a Claire Tomalin book, the script gets a little muddled at this point. Nelly is infatuated with Dickens’ writing, and seems to become even more transfixed after she meets him and attends his readings. But when she realizes that her mother is actually more pimp than manager, Nelly is angry and distraught. She tearily notes that she could never be his wife and later expresses disgust that one of Dickens’ friends lives with but is not married to his lover. “I did not realize that I was to be your whore,” Nelly says early in their relationship.

But Nelly then happily stayed Dickens’ so-called whore until his death, while Dickens took the shocking step of separating from the quietly dignified Catherine. In one of many excruciating scenes, he sends Catherine to deliver Nelly a birthday present from him. Scanlan’s Catherine projects calm and melancholy acceptance that she must share her husband with the world; it’s only when she hears of his intent to leave her that she breaks down, with Scanlan letting out a most anguished, choking wail.

Fiennes is somewhat creepy here, unattractively wigged and bearded, while behind the camera he frequently zooms so close to the faces of the illicit lovers they seem touchable. (His favorite shots are Nelly’s lovely neck and profile.) But he also gets right in there when the two first begin to become physically close, and their initial near-kiss, with Dickens’ hands on Nelly’s body and his whiskered lips skimming her face, borders on repulsive. It’s difficult to accept that the odd pair eventually finds happiness.

Jones, however, is a steely marvel whose lips and eyes are capable of conveying an incredible range of emotions within seconds. The film is told in flashback, with Nelly now in her late 30s and married. The gorgeous, long-view opening shot shows the adult Nelly purposefully striding across a panoramic beach; in the final scenes, she confesses her affair to a family friend who suspected, and though the speech Jones is tasked with is a bit purple, she lends it grief, sentimentality, and happiness even over a love lost, with her lips upturning ever so slightly every few words. Through most of the film, you may not quite believe how deeply Nelly loves Dickens. But in the last chapter, Jones convinces.