Season 12 continues its upward trajectory with a perfectly-fine adventure that makes better use of its pace.

Hey everyone! So, did I miss anything last week?

Okay, so yes, I did have to take a spare hour between watching a million films at the Sundance Film Festival to check out “Fugitive of the Judoon” after hearing all the hype and reading Beau’s glowing review last week (many thanks to her for keeping the ball of wibbly-wobbly, timey-wimey stuff in the air), and boy howdy that’s more like it. Based on the rest of the season that surrounds it, “Orphan 55” feels like a holdover script from season 11 they felt contractually obligated to produce, despite it clashing hard with the direction of this season. While “Judoon” set up all manner of intriguing arcs for later in the season (Dr. Ruth, the return of Captain Jack), “Praxeus” basically feels like a souped-up, much-improved version of “Orphan 55,” right down to doing the preachy environmentalism message better. It’s no great shakes for Who, but it’s still a delight to see a basically-workable sci-fi adventure come out of this lot.

“Planet Earth,” says The Doctor (Jodie Whittaker) in her finest David Attenborough soundalike, as the Earth floats in space. “Seven billion lives separate and connected, from the depths of the oceans to the edge of the atmosphere.” That sense of connectivity is the ostensible throughline of “Praxeus,” which sends the Doc and her team to three separate continents (an adventure teased in the closing seconds of “Judoon”) to investigate strange alerts that are mysteriously connected.

The episode takes its time to build, which is a refreshing change from the wham-bam pacing of previous Thirteen adventures. We don’t even see our first glimpse of Team TARDIS until five minutes have passed, Chris Chibnall and Pete McTigue’s script smartly setting aside some time to introduce the hour’s major supporting cast. This, of course, includes British astronaut Adam Lang (Matthew McNulty), whose module crash-lands in the Indian Ocean upon reentry; his husband, overly-keen former cop Jake Willis (“I’m on sabbatical!” he later asserts), played by Luther‘s Warren Brown; and a pair of travel bloggers, Gabriela (Joana Borja) and Jamila (Gabriela Toloi) traveling through Peru.

All of them are in different corners of the world, but find themselves running into mysteriously homicidal crows and mysterious messages. Jake is compelled by a text from the presumed-dead Adam to travel to Hong Kong, where he runs into Graham (Bradley Walsh) and Yaz (Mandip Gill). After Jamila is taken away by the aforementioned murder of crows, Ryan (Tosin Cole) arrives to help Gabriela find her. And then there’s the Doctor in Madagascar, who chases a reading to a mutated sailor who washes up on shore right next to the mobile lab of young scientist Suki Cheng (Molly Harris). She doesn’t get long to talk to the man before the plastic-y scales that cover his skin envelop him completely and he explodes… but, she does find out something alien crash-landed in the ocean from space, and it’s got deadly designs for the human race.

If there’s one thing Season 12 has learned, it’s that Team TARDIS works best when split up. I’m still with Captain Jack in last week’s assertion that three companions is too many (“I had a dream about this once”), but if we’re going to keep such an overstuffed TARDIS crew, they work best as the leads of their own little adventures. It helps here, especially, that “Praxeus” sets up a few interesting side characters and takes the time to flesh out their wants and needs. Jake’s the clear standout, Brown playing him like the gruff lead of a weekly police procedural suddenly thrown into the Doctor’s silly space adventures. But more than that, he’s a buttoned-up tough guy driven by his love for his partner, even though he offers up a laundry list of red flags to Graham in their heart to heart: “I don’t do emotions,” he admits. “Wow, so you’re really a catch then.”

After our team reunites, with all their supporting characters in tow, we start to learn how all these disparate mysteries tie together: the Earth’s being invaded by a deadly alien pathogen called Praxeus, which interacts with the plastic in our bodies to destroy our bodies from the inside out. The effect, to be fair, is quite creepy by the show’s standards — a gradually-expanding mass of ivory scales that forces you into inhuman contortions until you explode painfully into dust — and plays with an environmentalist message leagues better than “Orphan 55” did. Earth, it turns out, is the perfect breeding ground for Praxeus given all the plastic pollution we dump into our landfills and our oceans, which director Jamie Magnus Stone (of season 12 premiere “Spyfall”) points out arrestingly with disheartening images of a gyre covered in floating plastic debris. “Humans are poisoning themselves and their planet,” the Doctor reminds the gang, pointing out that microplastics are in everything — our air, our water, our food. Hear that, Doctor Who? You can totally get away with polemics about pollution, provided you work them into the plot!

Hear that, Doctor Who? You can totally get away with polemics about pollution, provided you work them into the plot!

But most refreshingly, “Praxeus” doesn’t just settle for a literal murder of crows puppeteered by living alien microplastics — there are darker, more sinister forces at work. Turns out young Suki, with her over-equipped lab in the middle of Madagascar, is a bit more tied into the goings-on than the Doctor expected: she’s an alien scientist who, along with her ailing crew, unleashed Praxeus on Earth to study the virus’ activity on such a plastics-heavy planet to find a cure. “Praxeus devastated my planet,” Suki breathlessly explains. Sure, she’s the ostensible villain, but her motivations come from the understandable impulse to find a cure for her people, even if she’s a real ends-justify-the-means kind of person. But her haste and hubris are her downfall — she administers the Doctor’s hasty, human-geared cure for Praxeus, which just accelerates the process and explodes her before they can find a solution.

This leaves the Doc and crew with only one way to save the Earth: use Suki’s shuttle to administer the cure in Earth’s atmosphere, even though it will end up killing whomever pilots the ship. Jake, hoping to overcome his insecurities about his astronaut husband, volunteers, offering up space for a tearful goodbye (until the Doctor, of course, TARDISes him to safety). It’s all very wishy-washy and exposition-y, but somehow the script manages to hold all these disparate elements together: character beats dovetail into plot machinations to the point where Jake’s epic almost-sacrifice saves the world and his relationship with his husband.

Let’s not be hasty: “Praxeus” is the bare minimum to which Doctor Who should aspire, breezy, whiz-bang sci-fi adventure with a bit of a political message and a focus on tight plotting, a workable pace and some acceptable supporting characters. But given the mess of season 11, and the ups and downs of season 12 thus far, “Praxeus” feels like Doctor Who getting the basic brief right. As a followup to the staggering implications of “Judoon,” you could ask for far worse. If the rest of the season’s back half stays at this quality or higher, we can count on a full-on return to form.

Random thoughts:

• Graham’s silence when Jake says, “I married an astronaut… can you imagine being married to someone that impressive?” speaks volumes of his still-lingering love for Grace. Walsh is still the show’s MVP.
• When I heard we were going to be dealing with an alien force that interacts with plastic, I thought we were going to see a return of classic Who baddies the Autons. Alas, no shop window dummies this time, but at least it’s a possibility the Doc brings up (“They’re not microbial.”)
• “We didn’t teleport into an active volcano. Result!” Thank God they’re giving Yaz a bit more to do. Still waiting for more centralized stories with her, but at least she gets to be dashing this time around like the rest of Team TARDIS.
• I bet Matthew Waterhouse is kicking himself right now after learning that the Doctor can, in fact, use the TARDIS to save someone burning up in a flaming spaceship.

Doctor Who Series 12 Episode 5, “Praxeus” Trailer: