The TARDIS materialised in the empty forecourt of a 'gas station' in the United States of America. The only other presence on the tarmac was a scarlet, 1950s Chevrolet Impala. The TARDIS door swings open and a young, copper-haired woman steps out, followed only seconds later by a sandy-haired man.

"So... where exactly are we?" The man asks, gazing around. The TARDIS door opens again and the Doctor steps out, wearing a brown suede jacket with tassels and a familiar stetson.

"Texas!" He cried with glee, his arms outstretched. He tugged his jacket tighter around himself and shoved his hands into his pockets. Rocking back and forth on his heels, he inhaled deeply.

"Aah!" He sighed. "Smell that fresh, Southern air."

"Wow... Texas, eh?" said Amy. "So this is our anniversary present, is it?"

The Doctor peered at her out of the corner of his eyes. "Y-yes," he said after a moments hesitation. He grinned, and spread out his arms as a way of inviting his companion into a hug. "Happy anniversary!"

Amy smiled and threw her arms around the Doctor. "You know, for a moment there I'd thought you'd forgotten." She said, breaking away.

"Me? Forget my best friend's wedding anniversary? Nah, memory like a goldfish, me." He sniffed a indignant sniff.

"You mean an elephant." Rory said. The Doctor gave him a perplexed look; seconds later a look of comprehension appeared on his face. "Yes, well -" he began, frowning. "Anyway," he clapped his hands together, rubbing them gleefully. "Whose hungry?"

Amy and Rory hadn't noticed the diner across the road from the station. A large, pink neon sign reading "Mario's" hung above the door.

"Shall we?" The Doctor led the way over to the diner with his faithful friends trailing behind him.

The diner was almost empty, except for a heavily-built man with a mustache sitting at the counter, idly stirring a mug of coffee and perusing a newspaper. A young waitress with a blonde beehive was wiping down a table and the sound of swing music played from the jukebox in the corner. The Doctor, Amy and Rory sat down at the nearest table; the Doctor took off his stetson and rested it on the table. Amy leaned forwards and spoke in a hushed voice.

"So. How are things with you and River?"

"Oh you know. I visit her when I can. The rest of the time I'm having to rescue her from Sontarans or Judoon or from whatever predicament she's landed herself in." He sighed.

Amy giggled. "Well I'm glad she's keeping you on your toes."

"Just like her mother then." The Doctor muttered under his breath.

"Oi, you!" Amy said, slapping the Doctor playfully on the arm. Rory rolled his eyes.

"Oh stop it, you." Amy said, leaning over and kissing her husband on the cheek.

The blonde waitress walked over to their table with a small notepad and a pencil. She was wearing a very revealing, baby pink uniform and large gold earrings.

"Hey handsome," she said looking at the Doctor. "What's it gonna be?" She spoke in a Southern drawl.

"Two strawberry milkshakes, please." Amy said. "And..." She looked at the Doctor.

"No, nothing for me thank you," said the Doctor. "I'm driving." He gave Amy and Rory an exasperated look. "As usual."

The waitress looked at Amy with a look of utter disgust, then looked down at her notepad, scribbling her orders. Then she turned and walk back to the counter, absent-mindedly blowing a bubble with her chewing-gum.

"Hey Sandra, you heard this?" The man with the mustache called out to the waitress. "Heard what, honey?" replied Sandra. She was in the process of pouring out the two strawberry milkshakes.
"About that ranch down in Roscoe." said the man. "You know, the one owned by that Bobby whats-his-ame. The oil tycoon."
Sandra inserted a straw into each of the tall glasses. "What about it?" She asked casually, picking up the milkshakes and carrying them over to the table where the Doctor, Amy and Rory sat, all three of whom had stopped their conversation and were now listening intently to the mustached man.
"Well, it says here that a Mr Bobby Lynch, owner of the Lynch Oil Company, is reported to be under investigation after an oil spillage at Mr Lynch's Westrock Ranch outside of Roscoe last week resulted in the deaths of many livestock in the area."

Amy cast a sideways glance at the Doctor. She knew what he was thinking. It was only a matter of seconds now.
Sandra walked back to the counter. "I'm telling you now, Wayne. There's been something going on for a while now at that ranch. I ain't gonna lie to no one about it. Cattle been dying out like its the plague or something."
The man - Wayne - looked puzzled. "What are you saying, Sandra?"
"What I'm saying, Wayne," Sandra went on, "is that this ain't the first time it's happened. I don't live too far out from Lynch's ranch, you know, and I gotta funny feeling about that Bobby fella. Wouldn't trust him as far as I could throw him."

"Excuse me," the Doctor said suddenly, standing up. "But I couldn't help but overhear." Sandra and Wayne both looked up at him as if he had just interrupted a private conversation. He grinned foolishly at them, wringing his hands.
"You were saying something about cattle dying?" He looked at Sandra expectantly.
"Yeah, well, that's whats been going on around here." Sandra said indignantly. "If you ask me, there's something in that oil being pumped out of that ranch. That's the only explanation I have for it." With that, she walked to the far end of the diner and began wiping tables again, as if for a way of avoiding any further interrogation from the Doctor.
The Doctor, meanwhile, had sat back down in his seat and was gazing thoughtfully at nothing inpaticular. Amy cast him a sullen look.
"Please tell me you're not gonna get involved. You always have to get involved! Can you please just mind your own business this time. It's supposed to be our anniversary." She reminded him. The Doctor turned his gaze toward Amy, although it was clear he wasn't paying any real attention to what she was saying.
Amy slumped back against her chair, folded her arms and sighed. "Oh, what's the use. You're just gonna go and stick your nose in anyway."
Rory put his arm around his despondent wife. "Well we don't have to go with him, do we? I mean, we could go and explore. Maybe go - " he paused, as if wondering whether what he was about to say next was at all sensible. "Shopping?"
Amy's eyes suddenly lit up. "Seriously? But you hate shopping."
"No I don't." said Rory.
Amy rolled her eyes at him. "Rory, you're a bloke. Blokes don't do shopping. But if you're offering - " she sat up and pecked him on the cheek. "I'm just gonna pop to the loo." And with that, Amy got up and walked off, leaving Rory and the Doctor in an awkward silence.

"So... what are you thinking?" asked Rory after a moment or two had passed.
"Sandra's right. It must be the oil." replied the Doctor, not looking at Rory. "But how can oil kill all those animals without being noticed until now?" He absent-mindedly lifted his hand and scratched his cheek.
"Okay, so while you're off investigating, me and Amy are going to go into the nearest town to do some - " Rory began.
"Yes. Yes, you better had." said the Doctor distractedly. "I need to have a word with this Bobby Lynch. Rory, take Amy to the nearest town and go shopping. I'm off to Westrock Ranch." And he got to his feet, placed his trusty stetson back on his head, and strode purposefully out of the diner. At the exact same moment, Amy reappeared from the restroom.
"Oh, so he's gone already then, has he?" She asked in disdain.
"Yep." Rory answered. "So, you ready?" As they made to leave, Sandra called to them.
"Say, where are you pair off to? Why, you haven't even finished your milkshakes now." The couple turned round.
"Oh, we're just off into town," Amy said, smiling.
"But the nearest town is 20 miles from here. Surely you ain't gonna be walking?" Amy and Rory looked at each other. Now that they thought about it, walking did seem a little foolish. It couldn't have been less than 40 degrees in the sun, and 20 miles was a heck of a walk in such heat.
"Well - "Amy began.
"I mean, I could give you a ride if y'all like." said Sandra. "My cars parked round the back. My shift ends in 10 anyway, I'm sure Mario won't mind."
"Um - " Rory started. He looked at his wife for an answer, as he thought it unwise to make a decision on the basis that it would appear quite inappropriate for him to accept such a generous offer from an attractive blonde woman without Amy's consent.
"Okay." Amy said. "Thank you."
And so Sandra went to check out whilst Amy and Rory waited.

"Oh, nice."
The Doctor stepped out of the TARDIS into the stuffy, moist barn. Flies buzzed about the rear ends of cows as he made his way outside into the blistering sun beating down upon Westrock Ranch. He tilted the brim of his stetson down to shield his eyes from the glare as he surveyed his surroundings. The dusty ground was barren and all that broke the monotonous landscape of red rocky mountains and skeletal trees was the occassional delapitated shed and broken-down carts. The Doctor stood with his hands on his hips, taking in the view.
"Bit of a fixer-upper if you ask me."He muttered to himself.
A hen suddenly appeared at the Doctor's feet, pecking at the ground for scraps.
"Oh, hello there, I'm the Doctor. Could you possibly point me in the direction of Mr Bobby Lynch?" He gazed expectantly at the bird at his feet as if hoping it would actually answer him, but it merely continued to scratch the ground with its beak and ruffle its feathers in an agitated manner.
"Fine. Be like that." Said the Doctor in an offended tone. He started walking about, frequently turning on his heel, looking in the opposite direction, then folding his arms and looking perplexed. All of a sudden, he felt a burning sensation ripping through his shirt and scorching his chest.
"Argh!" The Doctor winced in pain. He hastily took off his suede jacket and, plunging his hand into the breast pocket, withdrew the sonic screwdriver. It was glowing bright green.
"Yaah!" The Doctor dropped it instantly. The device fell to the ground, where it lay, making a dangerous hissing sound. Frowning, the Doctor bent down and peered at his screwdriver, utterly bewildered.
"What's got into you?" He asked out loud. As the Doctor stood staring at the burning device, the green light slowly faded and the hissing sound diminished.

The Doctor wrapped his hand in his jacket and cautiously picked it up. It had cooled rapidly, so he took it in his other hand and analysed the readings. He let out a moan of understanding as he squinted at the data.
"Third degree toxic residue, not of terrestrial origin." He lowered the screwdriver and sniffed the air suspiciously; screwing his face up in disgust, he remarked "Hmm, yes. Things do smell a tad iffy around here now you come to mention it." And, flinging his jacket over his shoulder, he marched in the direction of what he deduced was the source of the pungent odour.
He made his way around the barn and saw, a few hundred feet ahead of him, a large, timber-framed house. He marched up to the house, where, on the verander, an elderly gentleman sat in a rocking chair polishing the barrell of a large shotgun. Suddenly, a great, lumbering German Shepherd leaped from beside the man, barking viciously. The Doctor jumped back in alarm, though quickly made to smile to disguise his sudden panic.
"BRUTUS, HEEL!" bellowed the man. "HEEL!" The dog stopped barking almost at once, though it did not shift its gaze from the Doctor, its teeth bared. The elderly man got up from his chair and strode over to the top of the steps outside the house.
"Who the hell are you? What are you doing on my land?" He cocked his gun. The Doctor instinctively held up his hands.
"Woah!" He cried. The man glared at him. " Well, you see, the thing is - I was just passing and I - well I noticed you were looking for farmhands." He looked at the man, trying not to look suspect. The gun-toting gentleman scowled at the Doctor.
"But we ain't looking for no farmhands!" He growled. He raised his shotgun.
"Oh." The Doctor looked abashed. "I see."
The German Shepherd started barking again. The Doctor, who found himself staring down the barrel of a deadly firearm, decided it might be his cue to leave. He turned gingerly, and had taken only a few steps from the house when a young, female voice cried out.
"Daddy, wait!"
The Doctor stopped. He turned his head to see a raven-haired girl in the doorway of the house, looking at him. The Doctor gave her a fanciful smile and mouthed the word "hello."
The girl smiled back at him.
"Katelyn, what in God's name are you doing out here?" The man yelled at her.
The girl stood with her hands on her hips; a look of defiance overcame her pale, wide-eyed face.
"Daddy, put that gun down. I'm sure this man here means us no harm." The girl's father gave her a severe look, the turned to the Doctor and grunted.
"So," the Doctor said after a moments silence between the three of them. "Do you mind if I come in, it's rather warm out here. Although I suppose you're used to it." He gestured at the girl and her father. The man shot the Doctor a severe look. His daughter - Katelyn - however, smiled pleasantly at him.
"Why of course. Your mouth must be dry as a nun's gusset." And with that, she turned and entered the house. The Doctor followed her with enthusiasm, completely ignoring the look of utter contempt on the old man's face.

Katelyn lead the Doctor through the house into the kitchen. The Doctor looked about him at the spacious room; the white tiled walls gave it a clean, fresh atmosphere. Katelyn opened a cupboard, took out a glass tumbler and went to the sink to fill it with water.
"You saw me, didn't you?" The Doctor said suddenly. Katelyn looked over her shoulder at him and smiled. She handed him the glass of water.
"Why were you in our barn?" She looked him directly in the eyes as she asked him this.
"Oh, I was just..." he looked sheepish. "Well, I was just..." He waved his hand about as if trying to pluck an answer out of thin air. Evidently, Katelyn was not convinced. She raised a single eyebrow and turned to look out of the kitchen window. Just then, the Doctor remembered why he was here in the first place.
"You wouldn't happen to know where a Mr Bobby Lynch is, would you?" He enquired, leaning against the worktop with his arms folded, looking inquisitively at Katelyn.
"Who wants to know?" Katelyn replied.
The Doctor withdrew his sonic screwdriver again and activated it with a flick of his wrist.
"I have readings of potentially deadly toxic chemicals apparently somewhere on this ranch," he said, holding the screwdriver up but looking at Katelyn, "and there's a smell, I don't know if you've noticed. It's not a smell I often smell on ranches, and I've been to a few in my time, let me tell you. No, this is an out-of-place sort of smell." He gazed around the room as if expecting to stumble across a clue as to what the smell was. "A very out-of-place smell."

Katelyn turned to face the Doctor.
"Bobby Lynch is my uncle; he runs this here joint." The Doctor eyed her with interest. "He's in the oil trade. Uses this ranch to pump the oil from down below the ground and sells it on for a handsome sum. Made himself millions, has Uncle Bobby."
The Doctor frowned.
"You think there's something wrong. It's the smell, you've noticed it too, haven't you? What is it, Katelyn?"
Katelyn shrugged. "I'm not to know, am I? Don't know nothing about the business. I'm just here to look out for the cattle. That's the only thing I'm good for, Uncle Bobby says."
The word 'cattle' triggered a rush of memories inside the Doctor's head.
"What happened last week? There was a spillage, wasn't there?" The Doctor inquired.
"You heard then?" Katelyn replied, looking suddenly dismal.
"Well, more overheard." the Doctor said, attempting feebly to reassure Katelyn's seemingly worried thoughts.

Katelyn moved over to the kitchen table and sat down. The Doctor followed suit and took a seat across the table from her.
"One of our pumps broke down." Katelyn went on, looking down at her arms. "Oil went down into the river, killed all the fish. Cattle must'a drank the water. Killed them too. Didn't shine too good on Uncle Bobby, I can tell ya."
The Doctor leaned back in his chair and rested his hands on his stomach, his fingers interlocked. He looked thoughtful.
"And I suppose that's when you started noticing the smell?" He asked after a few moments contemplation. Katelyn nodded.
The roaring sound of an engine jolted the two of them out of their respective thoughts.
"It's Uncle Bobby. He's home." Katelyn got up, dusted off her gingham dress and ran toward the kitchen door. She turned back to the Doctor. "Don'cha wanna come and say hi?" she asked in an almost playful tone. The Doctor got to his feet and followed Katelyn back outside onto the verander. Outside the house in the midst of a cloud of settling dust, stood a sleek, bottle-green Pontiac Firebird, it's engine rumbling. The elderly man and the German Shepherd had got up to greet the arrival.
The rumbling stopped and the door of the Firebird opened; a tanned, broad-shouldered man stepped out. He had silver-grey hair tied back in a ponytail and his coffee brown skin appeared leathery. He held a thick cigar between his pearly white teeth.

"Uncle Bobby!" Katelyn ran toward the man with wide arms. Bobby Lynch chuckled.
"Katelyn!"
The two of them embraced.
"Uncle Bobby, I have someone who wants to meet you." Katelyn said, pulling away from her uncle's arms. She turned to the Doctor and gestured for him to come closer. The Doctor did so in a brisk, cheery manner. He extended his hand for Bobby to shake, which he did, grinning widely.
"Hello, I'm the Doctor. Mr Lynch, isn't it?" the Doctor asked.
"Well howdy, Doctor! And yes! Mr Bobby Lynch, CEO of Lynch Oil. What can I do you for?"
The Doctor thought it might be useful at this point to use his trusted psychic paper. He reahced into his back trouser pocket and whipped out a tarnished, black leather wallet. Holding it open in front of him, he exclaimed: "I'm from the Texas Secret Investigative Squad, based in... well, Texas. I'm here to investigate a mysterious oil spillage that happened around here last week some time?" He gave Bobby a look of feigned curiosity. Bobby's smiled diminished somewhat, and his eyes became set in a cold, hard glare. Katelyn reached out and touched her uncle's arm tentatively. "Uncle Bobby, this man can help. He's not like the others. He's..." she broke off and gave the Doctor a look of urgency. "I've seen this sort of thing before." The Doctor continued, taking Katelyn's hint. Bobby's expression seemed to soften. He took the cigar from his mouth, dropped it on the ground, stubbed it out with his heavy, booted foot and sighed."Well then," he said, looking back up at the Doctor. "You'd better come this way."