The hotel rooms are full of all manner of scary things, including a creepy clown, and Lucy finally stumbles across the one thing that terrifies her the most - a ferocious gorilla! Lucy begins to write a final letter - which ends with the phrase "praise him" - as a hulking Minotaur bears down on her.
Sometime later, the TARDIS team arrive inside the hotel. The Doctor is particularly excited - he's convinced that this isn't really a hotel, but some kind of alien environment made to look like once. He, Amy and Rory soon encounter the hotel's other residents - no-nonsense Rita, geeky blogger Howie and submissive mole-man Gibbis.
Rita quickly takes control of the situation, impressing the Doc. She explains that this is no ordinary hotel - the corridors twist and stretch, the doors and windows all lead to brick walls and the rooms all have "bad dreams" inside. The Doctor plans to return to the TARDIS to do a "planet-wide diagnostic sweep" - but his craft has now vanished!
Rita reveals that there's someone else in the hotel with them - a man named Joe, but he's currently tied up (literally!). The Doctor pays the deranged Joe a visit, finding him bound to a chair in a room full of perpetually-cackling ventriloquist dummies. As the Doctor takes note of his horse-shoe tie-pin and dice-shaped cufflinks, Joe rants about a creature coming to feast on them all.
Taking a gagged Joe with him, the Doctor warns the others not to enter any room they may feel attracted to. Howie turns out to be a bit of a conspiracy theorist - he's convinced that they're all trapped in a secret Norwegian city, built into the mountains in preparations for an alien invasion. Soon afterwards, he stumbles into the room containing his fear - turns out Howie is that rare beast, a geek who's afraid of girls!
Rory spots an exit, but it soon vanishes. The rest of the group hear the roar of the Minotaur and take refuge in different rooms - while Rita is faced with her disapproving father, Amy, Howie and Gibbis face the mole-man's fear - it's old Who foe, the Weeping Angels!
The Minotaur prowls the hotel and tracks down Joe, who is more than happy to sacrifice himself. The Doctor chases him through the twisting corridors, but catches up with Joe too late - he's already dead. Gibbis is concerned, but Amy insists that the Doctor has never let her down - even when she thought he had, when he left her as a child. In return, Gibbis kindly points out that if the Weeping Angels were for him, then Amy's fear is still lurking somewhere in the hotel...
Rita shares her theory with the Doctor about their situation - she's convinced they're in Jahannum, the Islamic Hell. Meanwhile, the Time Lord is confused - most of the fears in the hotel are unrelated to the surviving inhabitants, so why they still hanging around? Having discovered Lucy Hayward's note, Amy passes it along to the Doctor. In her final moments, Lucy revealed: "The gaps between my worship are getting shorter."
After hearing Lucy's message, two words begin to involuntarily spill from Howie's mouth - "Praise him". Convinced that Howie will be the Minotaur's next victim, the cowardly Gibbis suggests sacrificing him to save the rest of them but the Doctor insists that they will all stay together. Howie becomes possessed by a mysterious power and Doctor warns his pals that the force appears to feed on fear - they mustn't give in to it. But that's not his whole plan - "We're going to catch ourselves a monster," smiles the Time Lord.
Howie pleads with Minotaur to grant him a "glorious death" - his cries ringing through the hotel. The beast follow the source of the voice, but it's simply Howie's words coming from a speaker, amplified by the sonic screwdriver. The Doctor is able to trap the Minotaur and can communicate with the creature - turns out the hotel is a prison. The Minotaur has to "prepare" the inhabitants, but is running solely on instinct and yearns for the end.
Meanwhile, the unstable Howie convinces Gibbis to free him, insisting that the Minotaur will leave the rest of the group once it has him. The Minotaur hears Howie's summons and breaks free of the Doctor's trap. The Doc rushes off in pursuit, but once again, he's too late - Howie has been killed. Gibbis claims that the teen overpowered him, but everyone knows that the duplicitous mole-man is lying.
In a quiet moment, the Doctor and Rory wonder why the latter hasn't discovered his room yet. "After all the time I spent with you in the TARDIS, what was left to be scared of?" says Rory. But why is he speaking in the past tense? The Doctor picks up on Rory's words, but doesn't press the matter.
Running into Rita, the Doctor promises he will free them all from the hotel soon. When she accuses him of having a "God complex", the Doctor admits that he feels compelled to save his friends, since he's the one who placed them in danger. "Offer someone all of time and space and they'll take [it], and that's why you shouldn't," he explains. Nonetheless, he seems keen to spirit Rita away as his latest companion. But as the Doctor leaves, Rita finds herself saying those fateful two words - "Praise him."
Exploring the hotel, the Doctor finds his own room of fear, but the viewer isn't permitted a glimpse inside. "Of course," he says. "Who else?" He eventually stumbles across a room of monitors, into which all of the hotel's security cameras feed. The Doctor's hoping to locate the Minotaur, but instead spots Rita - aware of her fate, she's attempting to draw the Minotaur away from her new friends.
The Doctor begs her to reconsider, but Rita sacrifices herself, knowing that the twisty-turny hotel will prevent the Time Lord from saving her. Indeed, he can only watch the monitors helplessly as Rita is killed. After a brief bout of fury, the Doctor has a revelation - Rita was brave and calm in the face of death, so the link between the Minotaur's victim is not fear, but faith.
Howie believed in conspiracies, Joe's tie-pin and cuff-link proved that he was a gambler obsessed with the power of luck, while Gibbis has faith in the next band of oppressors coming to enslave him. "Every time someone was confronted with their most primal fear, they fell back on their most fundamental faith," reveals the Doc.
Rory has no faith or superstitions, so could see the exit, but the Minotaur's hanging around for Amy - she still has faith in the Doctor. The creature needs faith to survive, and has to convert it into a form it can consume. Soon enough, Amy begins to "praise him" and the group is forced to flee from the Minotaur.
They run straight into Amy's scary room - inside is little Amelia Pond, waiting forever for a Doctor who never came back. Now the Doctor knows that he has only one option - he must destroy Amy's faith in him. "I'm not a hero," he says. "I really am just a mad man in a box." He even calls her "Amy Williams" for the first time. Consoling his friend, he adds, "It's time to stop waiting."
With its food supply cut off, the Minotaur recoils and collapses in the hotel corridor. The hotel shifts and warps - it's revealed to be a spaceship and in its true form resembles something out of Tron. The Doctor explains that the creature that's been stalking them is both an alien and a Minotaur - it descends on planets to be worshipped.
The automated spaceship has been drifting through space, snatching up people with belief systems and converting their faith into food for the creature. But the systems haven't been functioning correctly for a while, which is why fears of the long dead weren't tidied away. As the Minotaur dies, it speaks of "an ancient creature drenched in the blood of the innocent", but it's not talking about itself - it's referring to the Doctor. The TARDIS travellers depart, dropping Gibbis home on their way.
And that's the end of that. Or is it? The Doctor has been profoundly affected by the events in the hotel, and drops his companions off at a new home on Earth. Rory even gets his favourite car as a gift. He excitedly rushes inside his house, but Amy senses that the Doctor is leaving them behind - this time for good.
He wants to end their friendship on good terms, and is afraid that Amy, Rory or both will end up dead if they continue travelling with him. Amy and Doctor share an emotional farewell, and Rory returns just in time to see the TARDIS depart. "He's saving us," explains Amy.
Inside the TARDIS, the Doctor travels through time and space - alone once more.
• Director Nick Hurran - who excelled with last week's 'The Girl Who Waited' - does another excellent job this week. 'The God Complex' is visually interesting and highly distinctive.
• There's been some criticism of David Walliams's performance, but in his defence, Gibbis is written as a broad, comic character. The Little Britain star does well with the material that he's given.
• So what was in the Doctor's room? He even refuses to answer when Amy asks him what Time Lords pray to. Will this plot thread be picked up on, or was it simply intended to get viewers' minds racing?
• On an emotional level, 'The God Complex' works incredibly well. But on a plot level, less so. The final reveal is all a bit abstract - the Minotaur needs faith to survive and feeds on it, but we don't learn any more than that. It's a fairly thin explanation for the events that preceded it.
• So the Minotaur is a distant cousin of the Nimon - a nice touch there for classic Who fans!
• Amy's goodbye to the Doctor is superbly written and well-played by Matt Smith and Karen Gillan. It's just a shame that Rory is given such short shrift in his (apparent) exit. That said, we've got a sneaky suspicion that the Ponds will be back...