"The Old Woman with the Knife" by Gu Byeong-mo follows a female assassin nearing the end of her career — a striking and compelling premise that has proven irresistible for adaptation.

The hardboiled Korean action-thriller novel, originally published in 2018, was reimagined as a musical last year and its film adaptation premiered at the 75th Berlin International Film Festival.

It follows the story of Hornclaw (played by Lee Hye-young), a 65-year-old assassin whose age is beginning to catch up with her, and Bullfight (Kim Sung-cheol), an enigmatic young man who trails her with unclear motives. Her line of work, already dangerous, grows more precarious as she ages, and the world around her begins to see her as obsolete.

“She’s like the legendary gunman whose hands have started to shake,” said director Min Kyu-dong at a press conference. “Then a hotheaded newcomer shows up and challenges her to a duel. When she refuses, he starts firing wildly to provoke a confrontation.”

Both the novel and the film center their narratives on this aging killer.

But while the book turns inward, delving into the psychological weight of growing old — questions of powerlessness and the meaning of existence — the film leans outward, embracing visual spectacle through action-packed confrontations, tense chases and uneasy alliances.

At its best, the film is not a retelling, but a divergent reflection of the same story — like a puzzle assembled from the same pieces, yet arranged into an entirely different picture.

Bullfight and Hornclaw: Rivalries in two registers

One of the starkest differences between the novel and the film lies in the characterization of Bullfight.

In the film, his backstory is clearer and more emotionally grounded, hinting at a traumatic event that not only fuels his obsession with defeating Hornclaw but also his desperate need to leave a mark on her life.

For the film to work, Bullfight’s world had to be as robust as Hornclaw’s, according to the director.

"What could have pushed a young man to seek out a showdown with an aging killer? Perhaps a traumatic event, powerful enough to upend his entire life, is what drives him," said Min.

“With a novel, if something doesn’t make sense, you can close the book and come back later. In a film, the moment passes, and if you don’t understand, the rest of the story might not land.”

The novel resists clarity. Bullfight’s motivations remain ambiguous, his feelings toward Hornclaw unreadable.

Gu has consistently declined to offer any clarification since the novel’s release. “It’s the part readers are most curious about,” she said. “But if I give a clear answer, the mystery disappears. I want readers to sit with their own questions.”

Power struggle

Another key divergence appears in the portrayal of the fictional company.

In the novel, the shadowy organization of contract killing is referred to only vaguely as “the agency." Both Hornclaw and her former partner and mentor, Ryoo (Kim Moo-yul), recognize the moral compromise inherent in their line of work, fully aware that their so-called “clean-up” jobs are, in the end, acts of unforgivable violence.

In the film, the moral framing is more ambiguous — even somewhat palatable. Hornclaw describes her work as a kind of sacred duty, targeting only those whose crimes seem to warrant death. There are boundaries, rules that govern her actions.

The agency's director, Son (Kim Kang-woo), harbors ambitions to modernize it and ultimately edge Hornclaw out. Their conflict deepens as Son aligns with the newcomer, advocating for new ethics and methods within the agency. This clash reflects not only generational tensions but also a clash over justice, efficiency and the value of human life, leaving the aging Hornclaw increasingly sidelined and dismissed.

Moral ambiguity

Similar to the ethics of the agency that Hornclaw clings to, the film portrays her as a figure holding onto some sense of justice and righteousness, with her first love, Ryoo, also lingering as a sacred yet mysterious presence in her past.

For example, Hornclaw’s first murder is deliberately ambiguous in the film. The novel, however, offers a harsher, more unsettling interpretation: Ryoo intentionally abandons the young Hornclaw in a dangerous situation, out of a need to take care of the offender.

Far from heroes, the novel suggests that neither Hornclaw nor Ryoo was innocent or virtuous. The novel devotes considerable space to Hornclaw’s troubled history: her years of drifting from place to place, during which she was driven to steal not out of necessity but recklessness, her fraught relationship with Ryoo, and her child (omitted entirely from the film). This portrayal adds a layer of moral ambiguity and emotional complexity to the story.

Many symbolic motifs — existence and disappearance, wounds, loss and recovery, salvation and violence — are intricately woven into the book. The film, likewise, is layered with motifs and puzzles. According to the director, even something as simple as a car’s license plate hides a code.

“I hope that discovering these subtle details will be a small but rewarding pleasure for the audience and book fans alike," said Min

"The Old Woman with the Knife" novel is available in English, translated by Chi-Young Kim, as well as in several other languages in 13 countries.