They step out of the TARDIS near the base of the stone building we saw earlier. "Behold, a cockerel!" cries the Doctor at the sight of a poultry-themed weather vane. "Love a cockerel!" Who doesn't? He pronounces the building a 13th century monastery. Amy seems pleased to have landed in Medieval times, but the distance strains of a Dusty Springfield song seem to conflict with that. The gang has a look around and fined a muddy hole in the ground with a pipe running through it. "DANGER CORROSIVE," warns the pipe. The Doctor deducts that the pipes was exposed when a "magnetic quake" hit just before the tsolar tsunami. He sonics the pipe. "It's a supply pipe, ceramic inner lining. Something corrosive." Yes, hence the writing on the pipe. Silly Doctor.
They go have a look at the monastery. As they're bounding up the stairs, the Doctor says, "I think we're here; this is it." This causes the companions to wonder if they came here by accident. The Doctor's kind of jittery and all "Of course by accident!" but he's always kind of jittery so it's hard to tell if he's nervously hiding something. Rory touches a stone wall and burns his fingertips. "They're pumping acid off this island," the Doctor says. "That's old stuff. Fresh stuff and you wouldn't have a finger." Have these people never watched The Simpsons? If you go traveling through time, don't touch anything. Partly because it will give your children lizard tongues but also because everything might be coated in acid. Where were we? Oh, yes! An alarm sounds. "Intruder alert!" The Doctor tells them that people are coming... almost. Almost coming? No, almost people!
Rory tries to offer a sensible suggestion about running away but the Doctor and Amy are running toward the oncoming danger and drag him along. They wind up in a room in one of the towers. Positioned in each of the window alcoves, people have been strapped into metal harnesses. They appear to be sleeping. At this point, some of the almost-people come charging in. Introductions are made, sort of. Amy notices that the new arrivals look just like the people in the harnesses. "What, are you identical twins?" Two more almost-people come in, wearing their acid suits. One of them is a woman; her instantly uptight bearing identifies her as the group's leader. Her name is Cleaves, and though it will be a while before anyone actually identifies her by name, that's what I'm calling her. The Doctor uses his psychic paper to identify himself as a meteorologist, sent to check the place out after the solar wave. Cleaves tells her coworker, Dicken, to check the intruders for bugs. The Doctor figures that this is an army-run factory in the 22nd century. The workers are contractors. The Doctor suaves his way into having a look at the factory's critical systems.