Seriously. Just. Wow.
"Midnight", I can safely say, is a Doctor Who experience unlike any other. In a series that had previously left me quite underwhelmed, this completely blew my mind.
This is bar none Russell T. Davies' greatest work. He tosses aside all of the DW typicality: the companion, the hideous monsters, the running... Even the Tardis takes a leave of absence. In their places, he gives us a claustrophobic,motionless, and tense 45 minutes of sheer paranoia - and boy is it amazing!
Here we find The Doctor leaving Donna behind at a spa while he boards a tour bus on its way around Midnight, or 'the diamond planet'. He gets acquainted and rather chummy with the other passengers to pass the time, until suddenly the bus stops unexpectedly in a place where no person has ever gone, and they realize that they are no longer the only passenger on board . . .
As we all know, Steven Moffat is the master in creating a disturbing, chilling, and very cerebral atmosphere. Remember "Blink"? He created a monster that was genuinely terrifying without being aggressive or loaded with prosthetic. Well, Davies does him one better here. This time, we don't even know what the monster is, or what it looks like. It's more of an essence, like a demon possession. It grabs hold of its victim and corrupts it. How? We don't know. Why? Don't know. And that's what makes it so horrific.
This seems to be The Doctor's strongest adversary to date. He can't use words to talk sense into it, or use his screwdriver to find out more about it, and as paranoia strikes everyone on bored, he can't even win their trust. There's nothing for him to fight, and he is left in the mercy of scared innocents that think of him as a risk to their own safety. In fact, this is the only time we've seen the 10th rendered completely helpless - and David Tennant plays to that beautifully! In fact, everyone in this episode did a magnificent job! It's just a gripping study in character and emotion from start to finish.
All in all, this was my favorite episode to date, and by the end of it, my heart was racing so fast, I just had to watch it again.