Gong Hyo-jin's 'Yubuna Killer' Crosses 10% Ratings as the Couple's Dark Past Finally Unravels

MBC's Yubuna Killer has been climbing its own ratings chart every single week since it premiered, and episode 6 made that streak impossible to ignore: a 10.2% nationwide household rating (Nielsen Korea), the show's first double-digit score and its sixth consecutive self-record. Starting at 7.4% in episode 1 and ticking up through 8.0%, 8.3%, 9.4%, and 9.8%, the drama has now held the weekend mini-series top spot going into its fourth broadcast week.

The show centers on Yoo Bona (Gong Hyo-jin), a contract killer who eliminates violent criminals, and her husband Kwon Taesung (Jung Jun-won), an investigative journalist who has been quietly pursuing many of the same cases from the other side. That irony, a married couple whose jobs put them on a collision course neither has fully acknowledged, is the engine the drama has been running on. Episode 6 made it hum louder.

The first meeting, in two very different versions

After Bona runs into Taesung at a crime scene while she is mid-assignment, she goes home and proposes a casual date. When Taesung smiles and asks whether she means a day like the one they first met, the two share a warm embrace. But Bona's inner monologue cuts through the sentiment: as long as he is out there chasing stories and she is out there taking targets, another close encounter is inevitable.

What unfolds next is the detail fans have been pulling apart since the episode aired. In a flashback, a younger Bona, dressed in a red devil costume and walking down a staircase, stumbles upon Taesung collapsed on the ground, blood on his head. She was there. He has no memory of it. That gap between what she carries and what he doesn't know exists yet is doing a lot of quiet narrative work, and episode 6 lets it breathe without immediately explaining it.

Bona's buried past: a burning orphanage and a Russian friend

The show has been laying breadcrumbs about Bona's history in fragments. An earlier sequence established that a young Bona escaped a burning orphanage, led by someone whose identity has not been confirmed, before eventually becoming the assassin she is now. The show keeps the details deliberately sparse, which makes each new piece feel earned.

In episode 6, Bona discovers a listening device planted inside a doll sent by Seulgi, a Russian friend she has apparently known for years. Her response is characteristically blunt. She contacts Bong Taemin (Kim Nam-hee) to pass along that Seulgi is coming to Korea soon, but Taemin flatly refuses any interest in meeting her. Whatever the three of them went through together is still largely unspoken, and the show is pacing that reveal carefully.

Taesung's nightmare and the Kingfisher connection

Taesung's past carries its own weight. He receives a cryptic text from an unidentified source praising him for keeping a promise, then wakes from a nightmare: bound, struggling in a forest, a blinding light closing in on him. He sits with the image of his sleeping wife and daughter afterward, and the scene communicates his fear without spelling it out.

His history with Kingfisher, the criminal organization, is the other thread the show is leaving unresolved. Taesung survived a near-death encounter at a Kingfisher shooting scene in the past, and he has since built a career investigating systemic social problems. But he abruptly dropped the Kingfisher story at some point, and the drama has not explained why. The threatening text suggests that connection is still very much alive.

Episode 7: the meeting Taesung actually remembers

Airing on the 21st, episode 7 promises to show the version of their first meeting that lives in Taesung's head. A still released ahead of the broadcast shows a past version of Bona standing dangerously close to the edge of a hospital rooftop. Exhausted by years of assignments and the creeping sense that the violence never stops, she had reached a breaking point. Taesung, in hospital clothes himself, spots her and reaches toward her, trying to pull her back.

This is, the production team confirmed, the moment Taesung believes their relationship began. The same rooftop, a second encounter shortly after, and the gradual question of how two people whose lives should have stayed completely separate ended up married. The production team described it as the emotional architecture behind everything viewers have seen the couple share so far.

Episode 7 also shifts tone with a lighter subplot: Bona invites her coworkers from the Durumi Electronics Sales Team 3, led by team leader Kim Bongpal (Sung Dong-il), to a housewarming. The team immediately convenes an emergency strategy meeting to figure out what gift to bring and, more urgently, why Bona would invite them in the first place. Given how the drama has balanced its thriller tension with ensemble warmth, it's easy to see why the production team is calling it one of the lighter episodes of the run.

With the show's ratings momentum showing no sign of flattening, the question going into week four is whether episodes 7 and 8 will push the record higher still.