The Doctor, hacking into their computers, congratulates Nasreen and Mack on their jolly big fuckin' hole, and then asks them, um, why. They still don't have a compelling reason. Seems they found some blue grass and some anachronistic minerals on the surface, and thought, "Big giant hole." Then he uses their computers and a lot of talking talking talking to figure out that the things drilling up are numerous transports. The Doctor tells them to gather up Ambrose and Elliot, as the only people who live here in the valley, and get out of there because in twelve minutes the gnomes are coming.
Not gnomes. I wish. Mack totally goes, "How can something be coming up, when there's only the Earth's crust down there?" Good question. The answer is "I won't tell you, but I will continue to make extreme demands of you and get mad if you don't fulfill them unquestioningly, for no real reason." Maybe he's worried about Amy and that's why he's being such a dick? Except that he does this to Amy all the time, also.
Anyway, Rory comes running up and says the graves are eating people, and the Doctor tells him to get inside the church with the Macks, since there's now an energy bubble all around the whole area, which consists of absolutely nothing save: Two graveyards, a house somewhere, a Big Mining Thing, and a church. Very strategic, this town. The Doctor demonstrates the bubble by pulling a slingshot out of nowhere, and it's very cute. What is cuter than a bowtied boy with a slingshot? Only in shortpants could he compete with himself right now.
Those damn gnomes. So apparently the TARDIS is useless because the bubble would screw her up, and anyway there are only nine and half minutes until gnomefall. Where's Amy? Doctor's not saying. He finally admits that she got eaten by the earth, while the TARDIS sings a little bit about it, but he assures Rory it's going to be fine. Rory sort of obliquely points out that, just like in every episode and multiple times in some cases, the Doctor has fucked up and gotten Amy in trouble. Which is not at all true: What gets Amy into her situations is invariably her retarded behavior.
The church door, sometimes it sticks, so that'll probably be a problem in a little while. You can tell because they yell, "This flaming door! Always sticking!" and "I thought you were having it fixed!" Right, because this family of four that is the only people who live here, they need to go to church all the time, where there are no services and nobody to administer them if there were. Inside, everybody takes a good five minutes to explain to the uncommonly stubborn Ambrose about how there's gnomes, and a sky bubble, and two missing people, all of which she was there for and is aware of, and so maybe she should pull it together and stop being a bitch for like one second. Ambrose is like, "Oh, I will not be pulling it together. I will be kicking it up a notch or two."