In The Magician's Apprentice, the Doctor has a lot to contend with: Davros, yes; the Daleks, of course; Missy perhaps; the complexities of time travel; his own shame; and a large helping of dramatic irony – in varying degrees.

There's quite a lot the audience knows that the Doctor and co. aren't entirely aware of, and depending on your point-of-view, this either adds to the drama, or utterly diffuses it. Case in point: Clara dies. Despite news that Jenna Coleman is leaving the show, she's already been seen filming for the rest of Series 9 (possibly with the exception of the final two-parter, Heaven Sent/ Hell Bent). When Michelle Gomez's Missy is exterminated, it's surprising yet a bit damp; she died in Death in Heaven, but here she is again. A little thing like death isn't going to stop her.

When Clara dies, you know this can't last.

And then the TARDIS is blown apart, and that's the final confirmation that these things will be undone.

That's the same problem with The Sound of Drums/ Last of the Time Lords (2007): the Master had decimated the Earth, so the only thing the audience expects is a big reset button. Indeed, the Paradox Machine was destroyed and everything wound back one year. But that's how smart Steven Moffat's writing is. Straight after blowing away Missy, Clara, and the TARDIS, he presents to us the means to reset things – only it's by doing something equally dramatic. It's something the Doctor will never do, because it's something he can't do.

He has to kill Davros.

Of course, we know the Doctor won't kill a child and substantially alter time. If he had done so before, the whole Time War could've never happened and Gallifrey would still be in the skies. There are too many subsequent paradoxes – prominently, if he kills Davros, there's no reason he would travel back to kill Davros, that timeline in which Clara is exterminated having been diverted.

(This, too, poses interesting questions: what would the Doctor be like without the Daleks (given his confession in last year's Into the Dalek that he found out who he was when he first landed on Skaro?)

Furthermore, we know the Doctor. We know who he is, and he wouldn't shoot a then-innocent boy. The Doctor, then, wouldn't, and he couldn't.

And yet – and yet...

Dramatic irony heightens/diffuses the suspense in other ways too: if you listened to rumours, you'd know Davros would be back, and that we'd be retreading old ground – both that we'd literally be back on Skaro, and that the Doctor's dilemma would be the same as in Genesis of the Daleks (1975).

Many have called the central concept a great idea, and indeed it is – although it's far from original. The same territory was explored in not just Genesis but also recent episodes like The Beast Below (2010), and to a lesser extent, Let's Kill Hitler (2011).

Additionally, Eleventh Doctor era stories have mulled over the Doctor's last days and what he would do – which is why the three-week party in 1158 doesn't quite ring true. Peter Capaldi's Time Lord is a different incarnation but he's still the same man, so why spend his final hours rocking out instead of spending time with his friends (The Impossible Astronaut), saving as many as he can (The Time of the Doctor), or both (Closing Time).

Capaldi, however, is really nailing the Doctor, and thankfully, much of the burden lumped on his shoulders by Series 8's "am I a good man?" arc has been lifted... or at least seemingly. That question hangs in the air still as he confront his shame at having left a young Davros to die amongst the hand-mines, and no doubt when he returns at the episode's cliffhanger.

Michelle Gomez, too, is great. Although I'm still not comfortable with the idea of a female Master, Missy herself is full of wit and dark charm. Her relationship with Clara is just as interesting as with the Doctor. There's an odd respect between them all, and a kind of trusting. Clara's reaction, while cautionary, isn't quite how you'd predict, especially considering Missy held at least some responsibility for Danny's death last series. Considering this is a companion hooked on danger and fashioning herself like the Doctor, Clara's taking Missy in her stride shouldn't come as too great a shock.

Kate Stewart's reaction, though, is a surprise. It simply doesn't ring true. I know Lethbridge-Stewarts are a strong breed, but she didn't convey much anger at the woman who flung her out of a plane, and killed one of her trusted advisors, Osgood.

That's not Jemma Redgrave's fault – she's always been a fantastic addition to the semi-regular cast – she was simply lacking in that sort of material. It's a shame, really, especially as UNIT was essentially deemed a necessary but inept plot device. I can only hope that it foreshadows events later on in this run of stories, notably The Zygon Invasion/ The Zygon Inversion, and, alongside the Doctor's confession, the finale.

There were so many elements to The Magician's Apprentice that some were bound to be left unexplored. Fortunately, Davros isn't one. He's a joy – always has been.

And thankfully, we have Julian Bleach back as the evil genius. It's been seven years since he last played Davros (in 2008's Journey's End), but he slips back into the role effortlessly. His dialogue with the Doctor is naturally electric, and the two bounce off one another perfectly. He immediately cuts down the Doctor's assertion that the Daleks should never have been created with a simple line, accusing him of being a broken record: "This is the argument we've had since we met."

We're sure to get further chilling exchanges in next week's The Witch's Familiar, and while this opening episode was a mixed bag, it should slot into place much better after we know how this impossible cliffhanger, and the storyline as a whole, is resolved.

I know I speak for fandom as a whole when I say, I can't wait.

Images: BBC.