(2010 edit: Partners in Crime, no question. I retrospectively demote this two-parter to a 3 out of 10. Bah, humbug.)
Now, I don't honestly mind all that much if a story doesn't make absolute scientific sense, provided it makes some kind of sense. See, for example, Tim McInnerny's transformation at the end of Planet of the Ood - seems a bit implausible, but it makes a kind of aesthetic sense. And I could possibly have let pass the crimes of last year's Evolution of the Daleks if they'd been in any way consistent within the story. That's the least I ask of a DW story, coherence. Here are some of the major areas in which I felt Journey's End failed to provide even that.
1. Dalek Caan's secret plan. Why did he bother to rescue Davros at all if he wanted to see the Daleks wiped out? No Davros, no new Daleks, it's very simple. Ah, say some, but he is barking mad. Now there, I reply, you have it - an adventure story's failed outright if you point out holes in its plot and the best cover it can muster is that the chief plotter is mad. And how the hell is he supposed to have manipulated events across space and time throughout the rest of this series, orchestrating this final showdown, if he's mad and incapacitated? And if he can do that, then - being generous for a moment and assuming that he didn't undergo his revelation until some considerable time after he'd freed Davros - why didn't he just use his magic manipulatory powers to crush Davros like a bug?
2. Davros' much less secret plan. Speaking of mad. So Davros doesn't want to destroy absolutely everything, he wants to leave the Daleks' time-shifted 27-planet empire intact - that's fine. And he plans to destroy everything else with a weapon that cancels out the electrical bonds of matter itself, however one might achieve that - that's fine too. For some reason he thinks this will also break open the barriers between parallel dimensions and destroy all of those too, which makes less sense, except that Rose claims she's seen the process start in her own dimension ("the darkness", if you remember). Which makes bugger all sense when you consider that a) this would require that Davros' matter-dissolving weapon somehow works backwards in time, and b) it wasn't actually fired in the end.
So the obvious conclusion is that there are parallel universe Davroses and Daleks doing the same thing at nearly the same time. But this just opens up a raft of new problems. For a start, the wave of destruction is supposed to be unstoppable once started, so Rose and her personal pet Doctor are going to be pretty screwed before long. So's everything else, if the weapon does work across universes. And surely it must be so, because Rose is able to take advantage of the big holes it's already left (although those magically heal themselves up when the story requires it). All that hard work for nothing, eh? Let's face it, the whole issue was only raised as a flimsy pretext to get Rose into the story, and forgotten as soon as its work was done, but I think we all knew that anyway.
The other big problem is that this idea allows us to compare notes between parallel Davroses, and the first thing we notice is that the Davros in Donna's little pocket universe in Turn Left, and apparently the Davros in Rose's universe, didn't need to steal the Earth to use as part of the death ray's engine. So presumably any other planet of the same proportions could be used interchangeably, which seems a fair conclusion, and you'd expect to be able to find a few dozen alternative planets lying around the cosmos without looking too hard. So why did Davros draw attention to himself by stealing 27 planets everyone would miss (or if the choice of planets was part of Dalek Caan's supposed manipulations, why didn't Davros notice and intervene) when he could have stolen 27 insignificant balls of rock no one would have cared about? The really stupid thing is that he stole three planets from other time periods, thus drawing even more attention to himself, when he must have been able to find any number of alternatives on his chronological doorstep. It's all right though, he's mad, and that apparently explains everything. Yeah, clinically insane like a fox. A very, very stupid fox.
Isn't it funny how insane villains always want to behave just like sane villains, only on a larger scale and with less planning? You never see a villain with an insane plan to make everyone wear purple hats when there's a Y in the month, or an insane plan to make potato salad out of mashed-up cuckoo clocks, or an insane plan to sit in a corner dribbling, muttering to himself and furiously pumping his fist. Not that I'm suggesting that sort of thing should appear on DW, but it's just funny how insanity never seems to mean actual insanity, just a lack of forethought.
3. The Haagen-Dasz key, or whatever it was called. Someone's given the Earth a self-destruct mechanism? That's a f***ing stupid idea even before the Doctor points out how stupid it is. It's marginally convenient for this particular story, although it's brushed aside almost immediately, but under what realistic circumstances could that possibly be of any use? "In order to save the planet it was necessary to destroy it"?! The real clincher, or whatever the equivalent of "clincher" is when you're talking about something that makes the complete opposite of sense, is that this system was apparently intended for use "if the suffering of the human race ever got too much" - what?! "What shall we do about Darfur?" "Well, our hands are tied, we can't send in the peacekeepers." "Tell you what, we could blow up the whole planet..." "Yeah, that'll solve it!" Stupiddy, stupiddy, stupid. I suppose we should just be grateful it turned out not to be a plot reset after all.
4. Towing the Earth home. Come on. Come the hell on. So we'll take a rift through space and time that happens to run through Cardiff - and apparently still does even after the planet's been moved across the universe - and we'll literally use it as a literal towrope to, if you will, literally tow the Earth back across space. Literally. I'm not even going to discuss this.
Other disappointing things:
- Last week we had talk of the Time War being "time locked", which sounded mysterious and impressive, and not at all the sort of thing a twenty-first century human scientist with issues ought to be able to knock up on the fly, posthumously I might add.
- After a brief set-up appearance last week, the Shadow Proclamation and their Judoon footsoldiers play no part in this episode whatsoever, even as an aside. I thought I'd heard the leisure centre's lead Goth declare universal war in a way that spoke of further developments to come, but I expect that was just my ears playing tricks.
- "A Dalek empire at the height of its power" is defeated in about ten seconds with a few flicks of a keyboard. A keyboard, moreover, that finds itself in the Daleks' dungeon, yet is bizarrely connected to the entire Dalek fleet. Cue embarrassing scenes of companions flinging Daleks about like they used to in the days when the Daleks were even more rubbish than they are now.
- Echoes of the first series as an entire Dalek fleet vanishes into dust at a protagonist's mere gesture.
- In fact, far too much plot convenience altogether. I don't think I could really describe any one thing as a deus ex machina this time round, but there was plenty of pulling stuff out of thin air. I've seen someone describe this sort of thing as "rabbitus ex hatta", which is a phrase I quite like and intend to steal for future use.
- And finally, and predictably, the story just couldn't sustain the sheer volume of returning characters RTD felt compelled to throw in. The evidence is plain: the Torchwood cast had nothing to do all episode, Jackie and Mickey were brought in especially to do nothing, even K-9 magically appeared for all of five seconds to provide one more rabbitus ex hatta. There wasn't all that much point in having Rose in the story, except that RTD clearly wanted to trash - sorry, sorry, revisit the (already perfectly good) second series finale and was prepared to bend this story over backwards in order to do it.