The latest episode tries to be a corridor-chasing lark and a climate change allegory and fails mightily at both.

Part of the frenetic nature of Doctor Who is its wide scope, not just in time and space but in tone — it can be fun, monster-chasing romp one week, lore-building mytharc the next, trenchant sociopolitical treatise the one after that. But the worst Who episodes try to smush all of those together, forgetting that they only have 45-ish minutes to do the deed. The Chibnall era’s been chock full of those, but last week’s “Spyfall” series showed glimmers of promise, of the prospect that they might just have cracked the scripts on this one. But then “Orphan 55” comes along to disabuse us of that notion, reminding us that the glimmers — the dregs, if you will — of season 11’s writing foibles have yet to be exterminated.

It’s puzzling to see one of the worst, most slapdash Who stories of the Whittaker years come from Ed Hime, whose debut last season, “It Takes You Away,” was one of season 11’s most thought-provoking and well-paced episodes. Instead, we’re off to the races thirty seconds in, when Graham (Bradley Walsh) just happens to find six coupons for an all-inclusive intergalactic spa called Tranquility. When assembled into a cube, the coupons instantly transport him, the Doctor (Jodie Whittaker), Ryan (Tosin Cole) and Yaz (Mandip Gill) out of the TARDIS and into the spa.

While Graham is excited at the prospect of finally putting his feet up, it’s not long before the gang has to contend with tiny bug-like viruses infecting vending machines, and worse, a total security failure that results in a group of creepy alien creatures (called “dregs”) invading the spa and killing, well, just about everybody except the gang and a few select survivors.

Now, it might be tempting to leave it there, making a good old-fashioned base under siege episode of Doctor Who with a few sociopolitical wrinkles. Alas, Hime and director Lee Haven Jones go overboard with ambition, packing in about a season’s worth of ideas and only five minutes apiece to execute them all.

First, there’s the retreat itself, a luxury spa built on top of Orphan 55, an ‘orphan planet’ – one, the Doctor explains, that has been rendered uninhabitable. The dregs are native to the world, though, and want them off. Especially since, inexplicably, they’ve evolved to breathe carbon dioxide and exhale oxygen. (“Like an angry tree!” the Doctor opines.) In concept, they’re relatively effective beasties in terms of design — the suits are lovingly rendered — but all they get to do is stalk around and hiss, and the full-CG versions of them are shockingly tame.

But then there’s the overstuffed supporting cast, almost all of whom have some skeletons in their closet and some kind of clumsily-handled personal issue to sort out. There’s Bella (Gia Ré), who’s snuck onto Tranquility to sabotage it to stick it to her greedy mother, whom we only find out a half-hour in is Laura Fraser‘s greedy developer/security chief(?) Kane. Don’t forget Benni (Col Farrell) and Vilma (Julia Elizabeth Fogle), the old couple who finally plan to propose, before Benni wanders off the station (?) post-crisis and onto the barren planet outside, leading the gang to find and rescue him at Vilma’s obnoxious insistence (drinking rule: take a shot every time Vilma ends a line screeching about “my Benni!!!”). And and and, there’s more the Doctor isn’t telling the gang about what planet Orphan 55 really is.

Hime and director Lee Haven Jones go overboard with ambition, packing in about a season’s worth of ideas and only five minutes apiece to execute them all.

Every five minutes, the episode switches gears, refusing to commit to any one notion. First, it’s a base-under-siege episode; then, they’re trawling across an alien wasteland on a rescue mission. Then, they’re running through underground tunnels with strange Russian writing, Metro 2033 style and betraying each other. Then they’re back at the spa, running through even more corridors and rescuing yet another character who’s foolishly run off, before coming to a big, smashy-crashy conclusion and zapping each other back to their respective homes.

It all feels like a parody of a bad Doctor Who episode: much of the time, they’re at least able to make the corridor chases and misunderstood baddies mean something. But just like the surface of Orphan 55, there simply isn’t enough oxygen for all of it. Characters offer tearful, earnest goodbyes to each other before either departing or going out in a blaze of glory, when they’ve barely shared a half-dozen words. Crazy concepts that feel like the premises of entire episodes (see: the virus that moves from machine to human and back) are absolutely thrown into the background.

And the biggest, kookiest idea yet — that Orphan 55 is actually a post-apocalyptic Earth driven to destruction by climate change — is so insultingly handled it beggars belief. Yes, Doctor Who‘s always been a progressive show, but ending your episode with a self-righteous monologue to the companions (and, with a wink, the audience) about how climate change denial will turn you into literal monsters is preachy and strident even for Who.

It’s hard to count the ways on which “Orphan 55” fails, so it might be best to stop here (apart from some more thoughts below). But suffice to say the episode feels like a half-dozen concepts in search of an episode, and not even the most breathless Jodie Whittaker explanations — some of which consisting of the most shoehorned-in ADR I’ve heard in an episode of television, like cutting to a single dreg and hearing the Doc shout “look, it’s the leader, the alpha dog of the apex predators!” despite it looking like identical to the others — can save it. The characters are rubbish (even our leads), and no one has any time to make any of its wild concepts land, much less the basic horror atmosphere of the episode itself.

I sure hope that “Orphan 55” is the exception, and not the rule, for season 12’s adventures. Otherwise, the show’s in for a world of trouble.

Random thoughts:

• Oh, and let’s not forget that the hour also sucks on a craft level — the editing, in particular, really lets down all of the expository moments, not to mention whatever sense of terror we’re supposed to glean from the dregs. When they attack, it feels like we’re cutting to an entirely different universe.
• If I didn’t mention special guest star James Buckley (The Inbetweeners) or his character’s son, played by His Dark Materials‘ Lewin Lloyd, it’s because they, like so many of the other supporting cast, get so little to do among the madness. What is it with this season absolutely wasting brilliant British comic actors in disappointingly straight-faced roles (save for Buckley’s neon-green hair)?
• Speaking of wasted characters with ridiculous, cheap alien costumes, I have to give a mention to Hyph3n (“Hyphen with an E,” to which she’s constantly referred), played by Amy Booth-Steel, a cat-like alien who looked like a cross between John Candy in Spaceballs and a Jellicle Cat who’d gone into hospitality.
• Seriously, everything about the Benni/Vilma subplot drives me bonkers. So Benni gets grabbed while getting his girlfriend’s hat, is left alive, and presumably the dregs are just, like, carrying him around until he gets the chance to catch up with her and ask a) will she marry him and b) will they shoot him when they go outside? And all of this happens offscreen? Absolute bananas.
• Also, for an episode full of characters sacrificing themselves to buy the others time, the other characters sure do spend a lot of time standing and gawking as the dregs kill said character off-screen. Run, you idiot!
• Speaking of which, where did Kane come from after ostensibly doing that for the characters in the tunnels? She comes back, and the sight of her allows Bella to instantly reconcile with her despite doing nothing to earn it? And from there, they make another sacrificial last stand? Miss me with that, chief.
• In our brief TARDIS bookends, the companions at least clock that something’s off with the Doc (presumably reeling from discovering that her home is dead, and that everything she knows is a lie), and I wish the episode was more about that stuff. At least they’re figuring out that the Doc lies to them more than they imagine, and they’re starting to figure that out.
• Maybe next week, a pseudohistorical with Goran Visnjic as Nikola Tesla, will conjure up enough Timeless vibes to wash the taste of this episode out of our respective mouths.

Doctor Who Series 12 Episode 3, “Orphan 55” Trailer: