Doctor Who's Wartime Thriller Episode 'Boom' Is an All-Time Great

Ranging from zany to sentimental, the first episodes of Doctor Who's new season are a showcase for its more lighthearted charms. Streaming on Disney+ in the U.S., it's a soft reboot aiming to bring this British sci-fi icon to a wider audience. But last Friday's episode, "Boom," is where things really kick up a notch, giving a firm answer to the question of where (and why) new viewers should start watching.

Directed by Julie Anne Robinson (Bridgerton) and written by former Doctor Who and Sherlock showrunner Steven Moffat, "Boom" is a tight standalone thriller with sharp political themes. All you need to know beforehand is Doctor Who's basic one-sentence logline: The Doctor (Ncuti Gatwa) is an alien who travels through time and space with his human friend Ruby Sunday (Millie Gibson).

"Boom" drops them into a futuristic war, providing a fantastic stage for Gatwa's range as an actor. The Doctor is ancient, mercurial, fun-loving, and fueled by a deep well of empathy for all living things. After a couple of high-energy episodes, this story leans into his darker side.

On the war-torn planet of Kastarion 3, the first people we meet are two human soldiers struggling to cross a gloomy battlefield. One is suffering from temporary blindness, and his friend worries that he won't make it home alive. Disturbingly, he keeps trying to avoid an automated ambulance patrolling nearby — an early hint of this war's deeper dystopian world-building.

He's right to be afraid. When the ambulance scans the injured soldier, it deems his estimated recovery time "unacceptable." Instead of providing treatment, it executes him on the spot. Compressing his corpse into a tube, its robotic voice announces cheerily, "Thoughts and prayers!"

Most of the episode's runtime explores a nerve-racking standoff involving the Doctor, Ruby, and a couple of local characters, including a soldier played by Andor actress Varada Sethu. I won't spoil the details. What I can say is that Steven Moffat's skill for clever dialogue and dramatic tension is out in full force, and Ncuti Gatwa displays tremendous screen presence in a scenario that constrains the Doctor's typically frenetic energy.

The ambulance scene introduces a gruesome healthcare allegory that will resonate with viewers on both sides of the Atlantic. This arrives hand in hand with an explicit critique of commercial weapons manufacturers: a classic nemesis for the humane and open-minded Doctor, who always stands up for the little guy.

There have been plenty of war episodes in Doctor Who's six-decade history, many of them rooted in historical conflicts like World War II. Stories set in the future and/or in alien locations can be tricker, requiring the writer to introduce an entirely new setting in 45 minutes. "Boom" sets itself apart with a simple but clever piece of world-building: The soldiers on Kastarion 3 are referred to as Anglican Marines, a future offshoot of the Church of England.

Clad in uniforms combining body armor with a black-and-white clerical collar, the Anglicans are an explicitly Christian force. We only need a few throwaway lines to extrapolate the deeper context of this conflict, where the church is clearly attempting to colonize an alien planet. Individual soldiers may take comfort in their faith, but their background draws a direct connection between religious power structures and a pointless, profit-driven war.

"Since when was the church an army?" asks Ruby, shocked. "Since most of your history," the Doctor replies. "You've been living in a blip."

Doctor Who is known for its drastic shifts in tone and genre, and this season certainly lives up to that reputation. Contrasting with the darkness of "Boom," the season premiere was a goofy adventure featuring a snot monster and a bunch of toddlers, and Episode 2 was an alt-history musical fantasy starring the drag queen Jinkx Monsoon. "Boom" marks a triumphant comeback for screenwriter Steven Moffat after several years in the doldrums, reflecting his skill for darker and sadder stories.

Moffat's tenure as Doctor Who showrunner (2010-2017) was pretty divisive, criticized for his treatment of female characters and reliance on zany twists. "Boom" reiterates something I've long suspected: His writing is actually better when someone else is running the show. With its taut world-building and simple yet effective emotional arc, it reminded me of why I loved so many of his acclaimed early Doctor Who episodes like "Blink" (2007). It also adds a rewarding new dimension to Ncuti Gatwa's version of the Doctor — a character whose personality changes every few seasons when they "regenerate" into a new actor.

So far, Gatwa's Doctor is noticeably cooler than most of his predecessors, who tended to be kind of dorky. He also feels more explicitly queer, and uses slang that just wouldn't work when the Doctor was played by straight, white actors. Above all, he's more upbeat and less angsty than recent iterations. However, this episode emphasizes a central element of the Doctor's personality: He's always the same person under the surface, shaped by the experiences of his earlier incarnations.

Gatwa's performance in "Boom" invites comparisons to the tough and cynical Twelfth Doctor (Peter Capaldi), displaying a more morbid sense of humor than we've seen before. When Ruby quips that she was hoping to visit a beach instead of a war zone, the Doctor replies, "Give it time. Everywhere's a beach eventually." Later on he exclaims "Your lifespan sucks!" making light of the fact that he outlives all of his human companions. This sense of truly alien life experience is crucial to Doctor Who's success, in a show that perennially balances wacky sci-fi hijinks with sentimentality, political commentary, and horror.

"Boom" embodies a whole host of Doctor Who's greatest strengths, illustrating why the Doctor still feels exciting and unique after six decades on TV. It's essential viewing if you're a fan who hasn't tuned in for a while — and for new viewers, it's a perfect point of entry. 

New episodes of Doctor Who stream Fridays at 7/6c on Disney+.