Season 1, Episode 6: ‘Rogue’

For decades, cosplay has been a huge part of the “Doctor Who” fandom, with hardcore viewers rocking up to conventions or gathering to watch the show decked out in Tom Baker’s striped scarf or David Tennant’s slim suit.

“Rogue,” this season’s sixth episode, is a meta meditation on cosplay — a portmanteau of costume play — and obsessive TV fandom, as the Doctor (Ncuti Gatwa) and Ruby (Millie Gibson) travel to Regency-era England and face off against a shape-shifting alien species who want to “dress up and play at ‘Bridgerton.’”

Initially, the repeated explicit references to Netflix’s blockbuster show — as well as the enemies-to-lovers plot, the copious wisteria and the orchestral covers of pop songs — feel unnecessary. But it soon becomes clear that “Doctor Who” is engaging in cultural cosplay of its own.

The year is 1813, and the Doctor and Ruby set about immersing themselves in the party of the season. Ruby quickly gains the attention of the night’s host, the proud Duchess of Pemberton (Indira Varma, “Game of Thrones”) and shocks the rude Lord Barton (Paul Forman) with her 21st-century slang and feminist principles.

More than just an old-fashioned misogynist, Lord Barton is secretly a Chuldur, a member of a species of intergalactic social climbers who rise up the ranks by taking over the bodies of the powerful and interesting. First, they go for Lord Barton; later, the duchess becomes their next victim.

The Doctor has never met a Chuldur before — not that he knows of, anyway — but he can tell something’s up. Scanning the room, his eyes fall upon a brooding, aloof nobleman called Rogue (Jonathan Groff, a notable King George in “Hamilton”) and the orchestra plays Billie Eilish’s “Bad Guy” to really hammer the point home.

If Rogue is a Mr. Darcy type, then the Doctor is his Elizabeth Bennet. The pair engage in a rapid-fire back and forth, and a palpable tension simmers. Mid-flirt, they stumble upon the duchess’s sinewy, discarded corpse and, in unison, accuse the other of being the murderer. But when Rogue pulls a gun on the Doctor, revealing himself as a bounty hunter sent to track these monsters down, the stakes become much higher.

Rogue traps the Doctor on his ship, planning to send him to an incinerator. The Doctor doesn’t take the threat too seriously, and playfully blasts Kylie Minogue’s “Can’t Get You Out Of My Head.” “Boy, your lovin’ is all I can think about,” Minogue sings, and the Doctor mouths along, winking straight at Rogue.

Rogue lets him go, and the pair bond over their shared experiences of loss; the Doctor for his destroyed home planet of Gallifrey, Rogue for the partner he used to travel with. It’s a tender moment, and the pair lean in to kiss before they’re interrupted — predictably abruptly — by an alert that the trap for the Chuldur is ready.

Ruby has been making some discoveries of her own. On the wall of the duchess’s grand home, she spots the face of the actor Susan Twist in a painting of the duke’s mother — Twist’s cameo for this episode. (The trailer for next week’s two-part finale shows that Twist’s recurring appearances will finally be explained, and indeed play a crucial role in the season’s arc.)

The Doctor and Rogue reunite with Ruby, and the Doctor proffers a theory. What if the Chuldur were drawn to this period because of the inherent “drama” around it? But it’s more than that. The Chuldur confide that they want to use their new positions of power to take control of Parliament, then wage wars across the world. “We’re gonna cosplay this planet to death,” the duchess gleefully crows.

Knowing a scandal is the best way to get the duchess’s attention, the Doctor drags Rogue onto the dance floor and they dance together. Yet when Rogue gets down on one knee, pulling a ring from his pocket, it’s the Doctor who’s on the back foot and runs off, flustered.

The duchess and Lord Barton follow, screeching that they “must play them” before assembling their “Chuldur family.” When they transform from their Regency hosts back to their Chuldur forms, their visible heads and shoulders are a mixture of different animal species, feathers and fur.

Back in the ballroom, this transformation horrifies the guests, as the duchess proudly declares that “a party isn’t a party without a costume change.” The Doctor and Rogue watch on from their hiding place as she introduces the “season finale,” and Ruby walks in on the arm of the Chuldur Lord Barton. The shape shifters have “got her” too, the Doctor realizes.

Heartbroken, he thinks of the promises he made to keep Ruby safe, and sobs, before asking Rogue how long Chuldur live for. When he’s told 600 years, he spits back: “Good. That’s a long time to suffer.”

Bursting into the ballroom to object to the nuptials — prompting excited reactions from the Chuldur — he activates Rogue’s trap and the wedding party. But Ruby’s imploring eyes and quivering bottom lip tell the Doctor she’s not a Chuldur, and when she rattles off facts about her unknown heritage, the Doctor realizes if he incinerates the Chuldur, he’ll kill Ruby too.

For the Chuldur, it’s a near victory. “You’re too soft and feeble to dispatch your little blonde friend,” the duchess jeers. But if he doesn’t, Rogue points out, the Chuldur will kill Ruby, then the rest of humanity, anyway. “Can you lose your friend to save the world?” he asks, offering the Doctor his very own trolley problem.

In the end, Rogue makes the decision for him. He pulls the Doctor into a passionate kiss, a romantic moment befitting of a period drama. It’s not the first time two men have kissed on “Doctor Who,” but there’s no wink behind this act. That is, until Rogue swipes the detonator from the Doctor’s hand and leaps into the triform, pushing Ruby out to take her place. The ground falls out from beneath him, bounty hunter and bounty vanishing in one.

Distraught at yet another loss, the Doctor staggers forward onto the empty dance floor, shaken, where he and Ruby hold each other and weep. The Doctor briefly allows himself to feel his most human emotions, before shaking himself back into action.

For the Doctor, there is only forward. But with Rogue’s ring on his finger and the bounty hunter’s departing words (“Find me!”) hanging in the air, it’s clear we’ve not seen the last of Groff’s romantic Rogue.