‘Star Trek: Strange New Worlds’ Season 4 Episode 4 Recap and Ending Explained: Una’s Klingon Occupation Gambit

‘Star Trek: Strange New Worlds‘ just delivered one of its boldest genre swings yet, and the internet is still buzzing about it. Episode 4 of season 4, titled “A Case of Chiaroscuro,” trades the Enterprise’s usual color palette for a stark black and white homage to classic film noir, and the result is being called one of the show’s most stylish hours to date.

The episode centers on Commander Una Chin-Riley, played by Rebecca Romijn, as she leads her first away mission since her promotion. What starts as a simple probe retrieval spirals into a tense Klingon occupation thriller, forcing Una into a moral gray zone that tests everything she claims to believe about right and wrong.

Una Chin-Riley Leads a Dangerous Away Mission

The setup is deceptively simple. The Enterprise is sent to recover a wayward probe called Angelo-1 that has drifted into the Mat’aar system, a region under Klingon occupation. Because the probe strays too far from the demarcation line for a tractor beam retrieval, Una, Dr. Joseph M’Benga, and Ensign Nyota Uhura take a shuttle down to grab it themselves.

Nothing about the mission stays simple for long. The away team gets stranded on Mat’aar XII, a planet whose sun emits radiation that renders everything, including the episode itself, in black and white. It is a striking visual gimmick that critics have praised as one of the season’s most inventive concept episodes.

Complicating matters further is a bizarre twist. Una discovers she has an exact double on the planet named Nevette, who had been secretly collaborating with the Klingon governor while actually working undercover for the local resistance. When the away team learns Nevette was murdered, Una is forced to impersonate her double to survive and keep the mission from unraveling.

“A Case of Chiaroscuro” Leans Hard Into ‘Casablanca’

The noir homage is not subtle, and reviewers have made the comparison explicit. One recap described the episode as essentially “Casablanca in space without the love triangle,” complete with hard-boiled narration and a dark and stormy atmosphere.

Critics have noted that while the episode does not quite reach the heights of the show’s all-time classics, it stands as an intriguing twist on what is essentially a real life holodeck episode, giving Romijn a chance to do something meatier than her usual Number One duties. That praise for Romijn’s performance is echoed elsewhere too. One review called it series best work from the actress in an episode that juggles far too many premises at once.

The occupying Klingon force is led by Commander Kor, played by Demore Barnes, a younger version of the very first Klingon ever introduced on ‘Star Trek: The Original Series.’ Kor was originally played by John Colicos in that 1967 episode “Errand of Mercy,” and the character later returned in ‘Star Trek: Deep Space Nine.’

The title itself comes from an Italian art term referring to a strong contrast between light and dark within a composition, which fits both the visual style and the episode’s central theme that nothing on Mat’aar is truly black or white.

Nothing Is Black and White

The endgame of the episode hinges on a ticking clock. Una, M’Benga, and Uhura learn the Klingons plan to strengthen their planetary defense grid to permanently seal Mat’aar off, prompting the resistance to plot an EMP detonation to knock out Klingon technology first.

The real gut punch comes from a character named Roman, who murdered the real Nevette and is the only person who realizes Una is an impersonator. Rather than killing Roman herself, Una plants the EMP detonator on him and manipulates the situation so the Klingons believe he is the saboteur, a move that effectively guarantees his death at Klingon hands.

When the EMP finally knocks out the Klingon defense grid, it also disables the D7 battle cruiser orbiting the planet, giving Una’s team the opening they need to escape back to the Enterprise undetected. Whether the resistance can actually push the Klingons off Mat’aar for good is left unresolved, which keeps the door open for the storyline to return.

The episode draws a clear parallel to Una’s own history of hiding her identity as a genetically engineered Illyrian for most of her Starfleet career, before she won her rights in a court martial. She justifies breaking Starfleet protocol by arguing that Starfleet is not always right, a line that underlines the entire episode’s thesis.

Meanwhile, back on the Enterprise, a parallel mystery unfolds. Lieutenant La’an Noonien Singh investigates missing data from the Angelo-1 probe, a thread that feeds her growing fear that she is succumbing to her own augmented DNA. The trail eventually leads her to Nurse Christine Chapel, who confesses she deleted the data to protect a former captain whose medical ship illegally crossed into Klingon territory to answer a distress call.

Uhura gets her own trial by fire too. Making her first trip behind enemy lines, she is captured and interrogated using the Klingon mind scanner, a device previously only referenced in ‘Star Trek: The Original Series,’ and she survives it by leaning into the true parts of her cover story rather than pure fabrication.

There is a lighter subplot running underneath all the espionage as well. Lieutenants Erica Ortegas and Scotty, having recently become genuine friends after publicly loathing each other, spend the episode bonding over lunch while Scotty cleverly manipulates the probe signal to help track the Klingon battle cruiser.

‘Star Trek: Strange New Worlds’ season 4’s new episodes continue to premiere Thursdays on Paramount+.

Do you think Una made the right call letting Roman take the fall, or did this episode push its “nothing is black and white” message a little too far?