Gaining access to a power station in a town you've spent most of your life in is just as difficult as one might imagine it would be. It wasn't as if they could just flash the psychic paper and pretend to be inspectors come to check on the turbines. Roger Campbell, the plant manager, used to coach Rory's football team when Rory and his son were boys, and Glenda Havermann, who ran the front office, played bridge with Amy and Karen's aunt; they would know if the three crazy kids they'd known their entire lives had suddenly changed careers.

Amy pointed this out to the Doctor. His solution was summed up in one simple word: "Reconnaissance!" When his three companions didn't immediately congratulate him on yet another brilliant plan, he went on: "We'll go on an information-gathering mission, find out the setup, see what's going on, find out the best time to gain access!"

For a 907 year-old alien who'd experienced all the wonder, sorrow, and brilliance the universe had to offer, he reminded Amy of nothing more than a seven year-old boy with a new spy kit. She expected at any moment he would pull out a pair of goofy sunglasses and claim they were "X-ray eyes". Before he could get his hopes up, she thought she'd set him straight on one issue: "I'm not wearing any silly disguises."

He scoffed. "Silly? All you'd have to do is put on a little bit of makeup, and…"

"No!" Amy reiterated.

The Doctor's face fell. "Well, then what's your brilliant idea?"

Amy wanted to remind him that it was not her job to flesh out his crazy schemes for him, but when he put on that wounded puppy look she just didn't have the heart. Fortunately, Karen seemed ready to contribute to his plan.

"Rory," she began, "you remember that blood drive the plant sponsored this spring? And the H1N1 vaccine clinic last fall?"

Rory saw where she was going and nodded. "Yeah, the hospital sends nurses over to the power station all the time!"

"All we have to do," she continued, "is show up in our uniforms and pretend that we're doing a blood pressure screening. Or…oh, I know! We can say we're there to screen for aspergillus or something. Rory and I will occupy the workers listening to lungs and doing cheek swabs or some other medical nonsense, and Doctor, you can pretend to be a…well, a real doctor, or a lab tech or something and wander around under the pretense of swabbing things for mold. Amy, you volunteer at the hospital sometimes; you can assist him."

"I like it!" the Doctor beamed.

"It sounds like the plot of a Scooby Doo episode," Amy complained.

"I like it even more!" the Doctor enthused. "Ooh, I get to be Fred!"

"Oh no way!" Amy argued. "You are so Scooby." Laughing, she caught Karen's eye. "I'm Daphne!" they each shouted at the same time.

The Doctor turned to the last of the group. "Which means Rory is…"

"Shaggy," Rory concluded dryly. "Fantastic."

Trying not to laugh, Amy gave him a sympathetic pout and squeezed his hand. "He so is!" she mouthed to Karen as soon as he wasn't looking.

"Well gang," the Doctor said, eyes sparkling, "let's get a move on!"

With Karen and Rory in their scrubs, and the Doctor sporting a borrowed lab coat and flashing his psychic paper, gaining access to the power station was easier than they'd thought. Karen brought along a bag full of assorted medical equipment and a stack of official-looking forms with lots of little ticky boxes, asking personal questions about weight, diet, mucous discharge and bowel habits. She and Rory set about taking people's blood pressure, listening to their lungs, looking in their noses, and doing any other distracting medical procedures that occurred to them. If anyone got too curious about what they were doing, they would frown down at their clipboards and order the person to produce a urine sample. There's something about holding a jar of one's own bodily fluids that serves to dispatch with any desire to ask questions.

Meanwhile, the Doctor, towing Amy behind him, had pretty much the run of the place. They'd tried to send along a junior foreman to act as guide and supervise his work, but one embarrassing and confusing conversation about fungi and its effects on the human body and several swift and sudden dashes around corners later the poor man was heading back to his desk, shaking his head and wondering what exactly had taken place.

As Amy had anticipated, the Doctor was like a kid in a sweet shop, skipping between gauges and valves with an enthusiasm better suited to a holiday theme park. He tried several times to stop and explain to Amy what a particular bit of equipment was and what it did, and how it could be improved upon, but eventually her silent, withering stares penetrated his shields and he stopped bothering. Amy thought their tour of the wonders of modern electrical production would never end, when finally the Doctor found what he was looking for.

"Ah, this should do it! Shift supervisor's office." Inside the office, he managed to find a work schedule for the plant. As expected, after five o'clock all of the office workers went home, and after ten o'clock only a few workers and a handful of security officers were manning the power station. The Doctor managed to copy down a list of the workers who would be present, and where each of them would be.

Not surprisingly, after studying the documents he'd "borrowed" from the power station, the Doctor determined the best time to gain entry would be sometime in the wee hours of the morning, when the plant was the most deserted. After the four made a hasty retreat, carrying along their medical equipment and boxes of "samples" and promising to be in touch if the results found anything alarming, Rory pointed out that they probably could have determined that on their own, without a need for him and Karen to risk their professional reputation.

The Doctor scoffed. "Yeah," he said, "but we wouldn't have had nearly as much fun, and I wouldn't have found the schematics I need to flesh out my brilliant plan."

"By the way," Amy put in, "just what is your brilliant plan?"

"All in good time, my darling Amy; just a few minor details to work out."

Rory nodded his head in agreement with Amy's eye roll. "I may be new at this, but so far I find myself slightly worried by your idea of what counts as a 'minor detail'."

Just ahead of them, the sound of Karen's cell phone rang from the depths of one of the bags she was carrying. It took a few moments to find the right bag and then dig for the phone. The group stopped just ahead of her as she finally answered on the last ring.

"Have faith, Rory: it always comes out right in the end!" the Doctor beamed.

Rory mumbled his answer just under his breath. "It's not necessarily the end that I'm worried about, but all the bits that happen in between."

A few weeks traveling with the Doctor, and Rory was finally getting used to the daily experience of mortal peril. He was also beginning to trust the Doctor: really, he was! He'd spent most of the first week alternating between stunned silence and angry indignation: this posture of gentle nagging was much more representative of Rory in his natural, relaxed state. It was a strategy he'd adopted after years of running around after Amy. It wasn't that he didn't trust her or he didn't like being included in her adventures: it's just that someone needed to be there to remind her of reality and the dangers that came with it. She needed someone to notice the warning label on the can of spray paint. She needed someone to observe that maybe the branch wasn't strong enough to hold both of their weights. Mostly, she needed someone to remind her that she was human and fallible and perishable.

The Doctor wasn't human, and Rory didn't know if he was perishable or not, but he was certainly fallible; Rory had witnessed that much. It seemed like the Doctor could use someone to remind him of that fact: Amy wasn't going to do it. In her eyes, the Doctor could do no wrong. For all of their sakes, someone needed to play the voice of reason; and if the Doctor could only see it, he'd realize that Rory's attempts to ground him in sanity, annoying as they might be, spoke volumes about the other man's growing acceptance for the madman with the blue box.

Rory continued to fret and argue with the Doctor until he was interrupted by Amy tugging at his sleeve. He followed her gaze to where Karen was standing just a few feet away from them, her mobile pressed to her ear. He hadn't heard any of the conversation up until this point, but he could make a fairly good guess at the content. As a nurse, he'd seen enough people receive bad news to recognize all the telltale signs: the stunned, awkward silence; the wide-eyed stares broken up by bursts of too-rapid blinking; the pale, bloodless face and shaking hands. He swallowed the lump forming in his throat; it dragged like molten lead down into the pit of his stomach.

Finally Karen took the phone from her ear. She stood awkwardly on the path, staring at her mobile with furrowed brows. Amy was at her side, gently reaching out a hand to rest on her would-be sister's shoulder. There was a pause before Karen seemed to register the touch. She met Amy's eyes and flinched in obvious pain. In the beat of a second her fragile composure collapsed. She screamed and pushed Amy's hand away. Rory stepped in to help, and the look that she gave him stopped him dead in his traps. She howled like a wounded animal, spinning 'round to escape the hands that reached out to comfort her.

It took the Doctor and some previously unseen setting on his sonic screwdriver to get her calmed down enough to drag her the rest of the way home.

It was some time after that they were able to get out of her what was wrong.