Series Ten, Episode Four — “Knock Knock”

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By Brandy DykhuizenBeing a long-time fan of big spooky houses, mysteries and Hercule Poirot, the aesthetic of “Knock Knock” was an instant winner for me. And the first 30-ish minutes crammed in a lot of fun, full of classic mystery tropes and “Don’t go in there!” silliness.

Bill and her friends found a goldmine of a housing deal in London, with low rent, giant shared spaces, and cozy rooms. Of course, if it sounds too good to be true it usually is, and it didn’t take long for the episode to turn downright scary as floors creaked, shutters slammed and flat mates began disappearing. Luckily for the renters, The Doctor insisted on lurking about and wearing out his welcome, regardless of Bill’s protestations.

Bill’s drawn-out attempt at getting The Doctor to bugger off post move-in was high in comedic value, but also worked to establish Bill as a companion with a life outside the TARDIS. Even though he stuck around the house a little longer than Bill would have preferred, his willingness to help her carry boxes and get settled into her new digs was very “(Grand)Dad helping to move into the dorms.”

Despite the fairly brilliant start, once we learned more about the whys and hows of the house snacking on its tenants, plot points began to feel phoned in. After a well-crafted buildup to a pleasantly creepy mystery, we learned the mansion was under the control of alien wood lice that consume tenants every twenty years in order to keep the lady of the house clinging to life.

But… why twenty years? Where did the wood lice come from? Why did the mother’s preservation result in a cloudy memory? Couldn’t we have used some sort of Doctor-silly-sciency explanation of why the bugs reacted to sound? With Doctor Who, the devil is usually in the details, but “Knock Knock” demanded we take all the technicalities at face value with little further thought.

Our requisite few moments outside the vault at the episode’s end was a welcome wrap-up to the previous twenty minutes of stretched-thin storylines. The series has been hitting it out of the park this season, so I suppose we can forgive it for pausing to catch its breath. (At least we’re that much closer to learning who Nardole is guarding so fiercely in the vault.)


Landline? What is this, Scotland?” – Felicity.

Nobody ‘just does’ anything.” – The Doctor.

Harry: “I’m scared!” The Doctor: “Don’t be.” Harry: “Why not?” The Doctor: “It doesn’t help.”

Hope is its own form of cruelty.” – Landlord.

You see? You don’t need to go to outer space to find monsters. There’s plenty of things that want to kill you right here on Earth.” – Nardole.

BEST MOMENT: The Doctor sticking around Bill’s house long after his welcome had expired.

EPISODE’S MVP: Who better to wrangle into a proper mystery than Hercule Poirot himself? The mustache may be gone, but David Suchet can still throw some “Oh, reaaalllly” eyebrows to rival Capaldi’s caterpillared frons.

'Doctor Who' continues on the BBC

© Copyright 2017, BBC Worldwide Limited. All Rights Reserved.


– So there’s a Pavel and a Paul? Did they just get a bit lazy with the names?

– Lovely foreshadowing early on when The Landlord’s brown overcoat blended in almost perfectly with the wood paneling behind him.

– I’ve hesitated to think The Master/Missy is inside the vault, simply because whatever’s in there knocked three times rather than gave The Master’s signature four taps. But who else would be noodling around on a piano before The Doctor joins him for Mexican takeout? Either way, it seems Moffat is content to tease this one out as long as he can.

– Why couldn’t the previous tenants have been brought back as well?

6.5 out of 10

Next: “Oxygen”, in one week.

Before: “Thin Ice”, here.