0404 "The Sontaran Stratagem"

Donna was standing at the controls of the TARDIS while the Doctor watched with a growing dread.

"I can't believe I'm doing this!" she crowed.

"No, neither can I. Whoa, careful," he shook his head, slamming a mallet down on the console as he lifted a lever. "Left hand down! Left hand down! Getting a bit too close to the 1980s."

The ship lurched violently.

"What am I gonna do, put a dent in 'em?"

"Well, someone did," he joked, wincing as Rose stalked into the room looking livid.

"I thought I told you to throw those damn mallets out!" she snapped. "Do ya have any idea the headache I get when you go 'round smacking her like that? Keep it up and I'm gonna hit you with one!"

He was saved from answering by the ringing of a mobile phone. Fishing in his pockets desperately, he avoided looking at his irate wife.

Rose shook her head and moved to stand next to Donna, stroking the time rotor apologetically before silently pointing at a dial.

"Two ticks to the left, Donna," she said quietly.

She obeyed, and nearly laughed when the flight smoothed almost immediately. "But, hold on- that's a phone!"

"Course it is," Rose answered easily. "It's my phone, at that."

"Why's he got it?"

The blonde shrugged. "Only one working number in it, and he's got all that room in his pockets."

She was stopped from her questions by a serious expression on the Doctor's face.

"Martha needs us, Rose."

Moments later they were appearing in an alleyway, just behind a familiar woman in a white coat who turned to smile at the sound of the TARDIS. The door flew open and Rose stood there grinning at her. The Doctor and Donna were behind her as Martha flew at the blonde.

"Martha Jones," the Doctor grinned as the two hugged, snatching her away for a hug of his own.

"Doctor, Rose! I missed you!"

"You haven't changed a bit!" he grinned.

"You're daft," Rose chided him. "Martha, you look fantastic!"

"So do you!" the black woman laughed. "How long has it been?"

"About twelve years or so now," Rose shrugged.

Martha blinked. "You… you haven't aged… I don't…"

Rose kissed her cheek. "Don't think about it, sis."

"How's the family?" the Doctor asked, changing the subject.

Martha's smile became slightly strained. "You know. Not so bad. Recovering. Hasn't been as long for us."

Donna stepped out of the TARDIS fully, a bit nervous to meet someone so close to the people she'd begun to consider friends.

"Right. I should have known. Didn't take you long to replace me," Martha said, obviously a bit hurt.

"Now, don't start a fight. Martha, Donna. Donna, Martha. Please don't fight. I can't bear fighting," the Doctor said suddenly.

Rose smacked his arm. "Stop it. Martha, you couldn't be replaced. Donna is another friend, one who wanted to see something more, just like you did."

"I've heard all about you," the redhead smiled, shaking Martha's hand. "They talk about you all the time."

"I dread to think," Martha laughed.

"No, no, no. They say nice things. Good things. Nice things. Really good things."

Martha covered her face. "Oh, my God, they told you everything."

"Only what we already knew," Rose said, tipping her head. "Who's the lucky man?"

"What man? Lucky what?" the Doctor asked, oblivious.

Donna elbowed him. "She's engaged, you prawn."

Martha grinned and held up her left hand, wiggling the fingers slightly.

"Really? Who to?" he asked in surprise.

"Tom. That Tom Milligan. He's in paediatrics working out in Africa right now. And yes, I know, I've got a doctor who disappears off to distant places - tell me about it," she directed the last part at Rose who was barely holding her giggles in.

"Is he skinny?" Donna asked, glancing at the Time Lord.

Martha shook her head, a bit embarrassed by the attention. "No, he's sort of... strong."

"I remember," Rose nodded. "He seemed really nice, and I'm glad you found him, after…"

She trailed off, remembering the aborted timeline and the year and a half that preceded it. When she learned so much about her altered humanity…

Sensing the dark turn of her emotions, the Doctor pulled his wife in, tucking her against him protectively.

"He is too skinny for words," Donna thumbed at him. "You give him a hug, you get a paper cut. Don't know how Rose has made it this long."

Martha laughed as Rose squawked a bit indignantly, wrapping her arms around his waist.

"Oi! I like him however he looks, ta!"

"I'd rather you were fighting," the Doctor pouted, a mock glare directed at Rose. "This is you and Sarah Jane all over again."

Before she could retort, a woman's voice came over a radio.

"Dr. Jones, report to base, please."

Martha held up a finger, and spoke into the radio. "This is Dr Jones. Operation Blue Sky is go, go, go."

She turned and motioned them to follow, which they did, exchanging looks as soldiers, jeeps, and lorries passed them.

"Unified Intelligence Taskforce, raise that barrier now!" a soldier shouted. "Leave your safeties on, lads, it's non-hostiles!"

Another called over a bullhorn, "All workers lay down your tools and surrender!"

"Greyhound Six to Trap One. B Section, go, go, go! Search the ground floor, grid pattern Delta," Martha commanded into her radio.

"What are you searching for?" the Doctor asked curiously.

"Illegal aliens," she quipped.

The soldier with the bullhorn called again for the workers to surrender, and Rose squeezed the Doctor's hand. The soldiers forced the workers to their knees, hands over their heads.

Martha continued issuing commands. "B Section mobilized! E Section, F Section, on my command!"

She headed off then, leaving the other three standing in a bit of shock.

"Did you turn her into a soldier?" Donna asked, frowning.

The couple looked at each other nervously. Had they?

When Martha returned, the Doctor pointed at her badge. "You're qualified now? You're a proper doctor."

She smiled. "UNIT rushed it through, given my experience in the field. Here we go," she nodded, leading them across the grounds toward some people. "We're establishing a field base on site. They're dying to meet you."

"Wish we could say the same," Rose muttered.

The field base was in a lorry, decked out with all the technological equipment needed to communication with UNIT proper. Martha seemed entirely too comfortable around the soldiers, moving directly to the obvious commanding officer.

"Operation Blue Sky complete, sir. Thanks for letting me take the lead. And this... this is the Doctor. Doctor, Colonel Mace."

Mace saluted smartly. "Sir."

The Doctor cringed. "Oh, don't salute."

Mace shook his head. "But it's an honour, sir. I've read all the files on you. Technically speaking, you're still on staff. You never resigned."

Rose tried to hide her smirk. "Look out, Doctor, you've got a proper job. Next it's curtains and carpets."

"Shut it," he warned.

Donna blinked. "What, you used to work for them?"

"Yeah. A long time ago, back in the 70s - or was it the 80s? It was all a bit more homespun back then," he explained, glancing around.

"Times have changed, sir," Mace said by way of explanation.

"Don't mind him," Rose smiled charmingly. "He's not that good at going back. And you might wanna stop with the sir. You'll have his skin crawling and it'll take me all day to calm 'im back down."

"Come on though, Doctor. You've seen it. You've been on board the Valiant. We've got massive funding from the United Nations, all in the name of Homeworld Security," Martha said, her eyes alight.

Rose jerked slightly at the mention of the Valiant, stepping a bit closer to her husband.

"A modern UNIT for the modern world," Mace agreed proudly.

Donna drew herself up and lifted her chin. "What, and that means arresting ordinary workers? In the streets? In broad daylight? It's more like Guantanamo Bay out there. Donna, by the way. Donna Noble, since you didn't ask. I'll have a salute."

The colonel looked at the Doctor, seeking direction, and the Time Lord nodded at him, deciding he might just love Donna a bit in that moment.

Mace gave the redhead a smart salute. "Ma'am. And this would be…?" He gestured to Rose.

The blonde shook her head. "No one important, Colonel. Just Rose Tyler."

He clenched his jaw and saluted her as well. "On the contrary, Ms. Tyler. UNIT considers you a person of great interest and importance, to be treated with all due respect."

The blonde laughed. "Wouldn't Mum love to hear that? Anyway, don't salute me. I might let it go to my head and start giving ya commands."

Donna smirked. "Feel free to keep it up for me, though."

The Doctor shook his head, getting them all back on track. "Tell us what's going on in that factory."

The colonel immediately gave report. "Yesterday, fifty-two people died in identical circumstances right across the world, in 11 different time zones. 5am in the UK, 6am in France, 8am in Moscow, 1pm in China—"

"All at once?" Rose asked in surprise. "That's all the time differences, right? So they all died at the same time, yeah?"

"Exactly. 52 deaths at the exact same moment worldwide," Mace confirmed.

"Well done, love," the Doctor praised. "Tell me, Colonel Mace, how did they die?"

"They were all inside their cars."

Martha spoke up then. "They were poisoned. I checked the biopsies. No toxins. Whatever it is, left the system immediately."

Rose frowned. "That sounds sorta impossible."

"What have the cars got in common?" the Doctor asked.

Now their friend smirked. "Completely different makes but all fitted with ATMOS. And that is the ATMOS factory."

The Doctor shook his head. "What's ATMOS?"

Finally Donna piped up, never one to keep quiet when she knew something. "Oh come on, even I know that. Everyone's got ATMOS."

She brought them inside and they toured the facility looking for something that stood out.

"Stands for 'Atmospheric Emission System'. The ATMOS in your car reduces CO2 emissions to zero."

"Zero? No carbon? None at all?" he asked in genuine surprise.

"And you get sat-nav thrown in, plus 20 quid in shopping vouchers if you introduce a friend. Bargain," Donna threw in.

"Bargain yeah," the blonde woman agreed. "But how's it sucking all the pollution out? And where's it going? I mean, if it's so great, how come they're throwing in all that other stuff?"

The Time Lord smiled at his wife. Still asking all the right question. Rassilon, he loved her.

"And this is where they make it, Doctor, shipping worldwide," Colonel Mace said, approaching the group. "Seventeen factories across the globe but this is the central depot, sending ATMOS to every country on Earth."

"And you think ATMOS is alien?" the Doctor said, peering around at the facility.

The soldier neither agreed nor disagreed, merely met the Doctor's eyes seriously. "It's our job to investigate that possibility. Doctor?"

He led them away, toward an office where one of the ATMOS devices had been set up for investigation.

"And here it is, laid bare," he said, gesturing to the machine. "ATMOS can be threaded through any and every make of car."

"Surely you checked it before they started sellin' it everywhere, didn't ya?" Rose asked, stepping closer to look at it, knowing she would never understand it.

"We did. We found nothing. That's why I thought we needed an expert," Martha agreed.

The Doctor slipped on his specs and moved to stand next to Rose, eying the ATMOS. "Really? Who did you get?"

She elbowed him. "Think about it."

He looked around then ducked his head a bit. "Oh, right! Me! Yes! Good."

Martha and the colonel left the room to make sure operations continued.

Donna leaned against the desk. "Okay, so why would aliens be so keen on cleaning up our atmosphere?"

"Very good question," the Doctor mused, turning back to the device.

"Maybe they want to help - get rid of pollution and stuff," the redhead suggested.

Rose snorted, not imagining that was the goal here. She wasn't alone in that belief, either.

"Do you know how many cars there are on planet Earth? 800 million," the Doctor explained in a softly concerned voice. "Imagine that. If you could control them, you'd have 800 million weapons."

He turned back and looked more thoroughly. Rose stood near, but offered no opinion. Donna watched him work for a few minutes before wandering out to find some way of helping.

"Ionising nano-membrane carbon dioxide converter –" he mused.

"Which means?" she prompted.

He glanced up and grinned. "Which means that ATMOS works. Filters the CO2 at a molecular level."

"We know about that," Mace said, coming back. "What's its origin? Is it alien?"

He moved closer. Entirely too close. He was nearly touching Rose, who tensed, vastly uncomfortable.

The Doctor frowned and stood, instantly protective. "No, but it's decades ahead of its time. Look, do you mind? Could you stand back a bit?"

"Sorry, have I done something wrong?" he asked stiffly, stepping back.

"You're carrying a gun. I don't like people with guns hanging around me, all right? Not to mention, I would appreciate if you didn't hover over my wife like that."

"If you insist," the colonel nodded. "The files on you never mention that you even have a wife."

"Even if I wasn't married to him," Rose snapped, "I wouldn't want an armed guard looming over me, right?"

The colonel left the room, stiff and at attention. Martha had come in just in time to hear the exchange.

"Tetchy," she commented. "I didn't think to mention your relationship. I thought you'd prefer to keep it private."

"Well, it's true, and I would," the Doctor said, a bit darkly.

"He's a good man," she tried to explain.

"People with guns are usually the enemy in my books. You seem quite at home," he turned and pointed the sonic screwdriver at the device.

"Rude," Rose sighed, relaxing slightly.

Martha bristled slightly. "If anyone got me used to fighting, it's you."

"Oh right, so it's my fault," he snapped.

"Well, you got me the job," she pointed out. "Besides, look at me."

He turned off the sonic and spun to face her. "Am I carrying a gun?"

Rose placed a hand on his arm, trying to calm him.

"It's all right for you. You can just come and go, but some of us have got to stay behind. So I've got to work from the inside and by staying inside, maybe I stand a chance of making them better," she explained, her eyes begging him to understand.

"Yeah?" he asked, brightening. "That's more like Martha Jones."

"I learnt from the best," she shrugged.

He blushed a bit, missing the wink exchanged between his wife and former companion. "Well..."

Martha fought the smile on her face. "Yeah. Rose is just really good like that."

He gaped at her for a moment before bursting into laughter, the women joining him as Donna reentered the office.

"Oi, you lot!" she smirked. "All your storm troopers and your sonics - rubbish! Shoulda come with me."

"Where've you been?" Rose asked curiously.

The Colonel reentered, careful to stay near the door so as not to antagonize the Doctor.

"Personnel," the former temp answered. "That's where the weird stuff's happening - in the paperwork. 'Cause I spent years working as a temp, I can find my way around an office blindfolded, and the first thing I noticed is an empty file."

The Doctor shook his head. "Why, what's inside it? Or what's not inside it?"

"Sick days," Donna said simply, opening the glaringly empty folder. "There aren't any. Hundred of people working here, and no one's sick. Not one hangover, man flu, sneaky little shopping trip. Nothing. Not ever. They don't get ill."

"That can't be right," Mace replied, taking the folder with a look of disbelief.

Rose beamed at Donna. "I knew you were brilliant. You lot have been checking out the buildings, should've been checking out the workforce."

Donna nodded smartly.

"I can see why they like you," Martha nodded. "You are good."

Donna grinned. "Super Temp."

The soldier found nothing to make jokes or smile about. "Dr. Jones, set up a medical post, start examining the workers. I'll get them sent through."

"Come on, Donna, give me a hand?" the former companion asked the current companion.

The Doctor nodded, reaching almost absently for Rose's hand as he followed the colonel out of the room. She followed him without question, as she'd been doing for several years.

"So, this, this ATMOS thing, where'd it come from?" he asked Mace as they walked along a corridor.

The colonel didn't even look at them as he answered, "Luke Rattigan himself."

Rose frowned slightly, never having heard of that person. "An' himself would be?"

They went out to the field base and Mace pulled up the profile of a young man who was apparently a super genius.

"Child genius. Invented the Fountain 6 search engine when he was 12 years old. Millionaire overnight. Now runs the Rattigan Academy. A private school educating students handpicked from all over the world."

The Doctor grinned a bit. "A hothouse for geniuses - wouldn't mind going there. I get lonely."

Mace looked confused, but Rose rolled her eyes.

"You get full of yourself, is what you get," she teased lightly. "If we're going there, you're not gonna make all those poor kids feel stupid."

"I'll try," he winked.

The Doctor pointed at Mace as they headed back to where Donna and Martha had set up for physicals. "You are not coming with us. I want to talk to this Luke Rattigan, not point a gun at him."

Mace looked almost amused. "It's ten miles outside London. How are you going to get there?"

"Then get me a Jeep," he shrugged.

The colonel raised a brow. "According to the records, you travel by TARDIS," he said testingly.

Rose snorted. "You really think we're gonna take a technologically advanced time machine to the person who created something that we think is a weapon of hostile aliens? How'd you make it to colonel with thinking like that?"

"I see," Mace said stiffly, pointedly ignoring the gleeful look on the Doctor's face. "Then you do have weapons but you choose to keep them hidden. Jenkins?"

"Sir!"

The colonel turned to a young man and nodded curtly. "You will accompany the Doctor and take orders from him."

"I don't do orders," the Doctor assured him easily. Rose shook her head and elbowed him none too gently, causing him to gasp.

"Rude," she warned quietly.

Mace turned to Rose, deciding to try and skip over the Doctor if possible. "Any sign of trouble get Jenkins to declare a Code Red. And good luck, ma'am, sir."

He saluted smartly and the Doctor made a face. "I said no salutes."

The colonel shook his head and left the room, and Rose rolled her eyes.

"You just had to go and pick at him, didn't you? He's just trying to do his job, Doctor."

He was saved from having to answer y Donna joining them, looking a bit upset. "Doctor."

"Oh, just in time. Come on!" he exclaimed, grabbing her hand and tugging her in the direction of the jeep. "Come on, we're going to the country. Fresh air, geniuses, what more could you ask?"

"I'm not coming with you. I've been thinking. I'm sorry... I'm going home," she answered gently, pulling her hand away.

Rose stepped up quickly, her arm around the taller woman's back. "Donna, are you okay?"

"I've got to," the redhead said helplessly.

The Doctor nodded, taking a deep, bracing breath. This was going to crush Rose, but he would make it up to her. "Well, if that's what you want. I mean, it's a bit soon. We had so many places we wanted to take you. The Fifteenth Broken Moon of the Medusa Cascade, the lightening skies of Cotter Palluni's World, the diamond coral reefs of Kaata Flo Ko... Thank you. Thank you, Donna Noble. It's been brilliant. You-you've saved my life in so many ways, and been a great friend to both Rose and myself…" He started to hug her, then realized both his wife and his friend were staring at him in amused silence. "You're... You're-you're just popping home for a visit. That's what you mean."

Rose laughed, not even pretending to be sympathetic to his growing embarrassment.

"You dumbo," Donna said fondly.

"And then you're coming back?" he clarified.

"Do you know what you are? A great, big, outer-space dunce," the former temp laughed.

"Yeah," Rose said, finally moving to hug him. "But he's my great big outer-space dunce."

He grinned down at her, then at Donna. "I can't help it at times. You humans are confusing."

"Ready when you are, sir," the young soldier said then.

Donna elbowed the Doctor. "What's more, you can give me a lift. Come on. Broken moon of what?"

"I know. I know," he chuckled as the four of them climbed into jeep.

After dropping Donna to visit with her family, the rest of them drive on toward the school, chatting lightly.

"UNIT's been watching the Rattigan Academy for ages. It's all a bit Hitler Youth. Exercise at dawn and classes and special diets," Ross Jenkins was explaining to the couple.

"Turn left," a pleasant voice instructed.

Rose frowned at it, glancing at the Doctor before deciding to voice her concern. "Ross, one question. If UNIT think that ATMOS dodgy—"

He nodded. "How come we've got it in the Jeeps?"

"Fair question," the Doctor said, peering thoughtfully at the thing.

The young man let out a laugh that pegged him as anything but amused. "Ha, tell me about it. They're fitted as standard on all government vehicles. We can't get rid of them until we can prove there's something wrong."

"Turn right."

With a small grin, Ross said cheekily as he turned into the school drive, "Drives me around the bend."

"Oh, nice one," the Doctor approved even while Rose groaned at the pun.

"Timed that perfectly," the young man said proudly.

"I'm gonna be hearing that one again, ain't I?" the blonde woman asked with amusement.

"Most likely," the Time Lord agreed easily.

"This is your final destination," the ATMOS announced.

"Bit creepy that," she noted as they pulled to a stop.

They got out of the car and headed up the pavement, Ross following the alien and his wife as they watched the students jog past in exact formations.

"Is it PE? I wouldn't mind a kick-around. Got me daps on," the Doctor quipped. "Rose is brilliant with gymnastics, or she was years ago."

"Warning you, I will mix pears in all your food for a month," she threatened him under her breath.

"I suppose you're the Doctor," the young man who could only be Luke Rattigan said as he turned to survey them.

"Hello," he greeted him cheerfully.

The adolescent shrugged. "Your commanding officer phoned ahead."

The Doctor shook his head. "Oh, I haven't got a commanding officer. Have you? Oh, this is Ross. Say hello, Ross. And Rose, of course. Never go anywhere hardly without her."

"Afternoon, sir."

Rose waved, but didn't have a moment to speak as the Doctor suddenly rushed to the doors, dragging her along.

"Let's have a look, then! I can smell genius... in a good way."

Rose watched the Doctor wandering around the projects that students were working on inside. She couldn't help but grin fondly at him as he babbled to her about each one, telling her all about what each was for and where she might have seen something similar.

"Oh, now... that's clever! Look, Rose!" he cried as he slipped on his glasses. "Single-molecule fabric. How thin is that?! You could pack a tent in a thimble. Oh! Gravity simulators! Terraforming, biospheres, nano-tech steel construction! Ha-ha, this is brilliant! But y'know with equipment like this, you could, oh, I dunno... move to another planet or something."

The boy smirked a bit wistfully. "If only that was possible."

"If only that were possible," the Doctor corrected, pulling the glasses back off as he turned to Luke. "Conditional clause."

"Rude," his wife sighed, knowing she would never get through to him.

"I think you'd better come with me," the boy scowled fiercely before leading the three adults into his private living area. "You're smarter than the usual UNIT grunts, I'll give you that."

The Doctor feigned shock, turning to the young soldier with wide eyes. "He called you a grunt. Don't call Ross a grunt, he's nice. We like Ross. Look at this place..."

"Doctor," Rose warned him. "We're trying to do something here, yeah?"

"What exactly do you want?" the boy snapped.

"I was just thinking, what a responsible 18 year old. Inventing zero-carbon cars, saving the world..." the Doctor trailed off.

"It takes a man with vision," Luke said grandly, puffing out his chest.

"Mm, blinkered vision," the Time Lord mused.

Rose frowned. "That's right. 'Cause ATMOS means more people driving, more cars, more petrol, end result: the oil's gonna run out faster than ever."

The Doctor nodded proudly at her. "The ATMOS system could make things worse."

"Yeah, well, that's a tautology," Luke hurried to say. "You can't say ATMOS 'system' 'cause it stands for Atmospheric Emission System. So you're saying 'Atmospheric Emission System System'. Do you see, Mr. Conditional Clause?"

Rose put her hands on her hips. "Been a long time since anybody's said no to you, ain't it?"

He crossed his arms, pouting like the child he still was. "I'm still right, though."

The Doctor's tone became softer, more understanding. "Not easy, is it, being clever? You look at the world and you connect things - random things - and think, 'why can't anyone else see it? The rest of the world is so slow'."

"Yeah."

"And you're on your own."

The boy deflated slightly. "I know."

"But not with this," the Doctor said calmly, reaching into his coat pocket and pulling out an ATMOS device. "'Cause there's no way you invented this single-handed. It might be Earth technology, but that's like finding a mobile phone in the Middle Ages. No, no, I'll tell you what it's like! It's like finding this in someone's front room. Albeit, a very big front room."

He tossed the device to Ross, who caught it in a hurry. "Why? What is it?"

"It's the first step in gettin' us into trouble, again," Rose laughed slightly. "Another big old thing to be shiny and distracting."

He shot her a small quelling look. "Yeah, just looks like a thing, doesn't it? People don't question things. They just think, 'Oh, it's a thing'."

"Leave it alone!" Luke snapped.

"That's a great way to make him mess with it," Rose commented, cheerfully ignoring the look the Doctor had given her.

"Me, I make these connections and this to me looks like..." he walked into it and punched the button. "...a teleport pod."

As he disappeared, the blonde woman growled. "Ross?"

"Yes, ma'am?"

"Remind me to slap him when he gets back."

It was only moments later when he did return, coming out of the teleport at a run, snatching Rose's hand and placing her slightly behind him. "Ross, get out! Luke, you'd better come with me!"

He was followed by a very short, heavily armored soldier. The Doctor used his sonic screwdriver to short the controls.

"Making friends?" she asked, gripping his hand.

Ignoring her for the moment, he said loudly, "Sontaran! That's your name, isn't it? How did I know that, eh? Fascinating, isn't it? Isn't that worth keeping me alive?"

Ross aimed his gun at the Sontaran. "I order you to surrender in the name of the Unified Intelligence Taskforce."

"Oh, I can tell you that ain't gonna work," Rose told him. "Right, love?"

He nodded. "Cordalaine signal, am I right? Copper excitation stopping the bullets."

"How do you know so much?" the Sontaran demanded.

"Well..."

He began moving around the room, carefully keeping himself between Rose and the threat.

"Who is he?" the angry alien asked the teen.

Luke shrugged. "He didn't give his name."

The Doctor leaned against the desk, pulling Rose close. He might look casual, but she could tell he was tensed, poised for action the moment it was warranted. She gave him a quick squeeze to let him know she was ready.

"This isn't typical Sontaran behaviour, is it? Hiding? Using teenagers? Stopping bullets? A Sontaran should face bullets with dignity! Shame on you!" the Doctor said in a falsely light tone.

"You dishonour me!" the Sontaran shouted angrily.

"Then show yourself," he shrugged.

The Sontaran turned and announced, "I will look into my enemy's eyes." He removed the helmet to show a rather upset looking humanoid, short, brown, large head, no neck.

"Oh, my God," Ross gasped, obviously horrified.

"So that's a Sontaran…" Rose said thoughtfully. "I thought they'd be taller."

Shaking his head at her undaunted spirit, the Doctor merely asked, "And your name?"

"General Staal of the Tenth Sontaran Battle Fleet. Staal the Undefeated."

"That's not a very good nickname. What if you do get defeated? 'Staal-The-Not-Quite-So- Undefeated-Anymore-But-Never-Mind'?" the Doctor suggested.

Ross scoffed simply. "Looks like a potato, a baked potato. A talking baked potato."

"Now, Ross, don't be rude," Rose chided, sensing the Doctor's shift and moving a step away. "Don't you think we kinda look like pink weasels to him?"

The Doctor met her eyes briefly before bending to pick up a tennis racket and ball, bouncing the ball for a moment. "The Sontarans are the finest soldiers in the galaxy. Dedicated to a life of warfare. A clone race grown in batches of millions with only one weakness-"

"Sontarans have no weakness!"

Rose took her lead from the Doctor, knowing he was about to do something that would make them need to run and inched her way to Ross, plucking at his arm. The soldier needed be ready to go.

"No, it's a good weakness," the Time Lord assured Staal.

Luke shook his head in confusion. "Aren't you meant to be clever? Only an idiot would provoke him."

The Doctor waved the teen off. "But the Sontarans are fed by a probic vent in the back of the neck. That's their weak spot, which means they always have to face their enemy in battle. Isn't that brilliant? They can never turn their backs!"

"We stare into the face of death!" Staal announced proudly.

"Yeah? Well, stare at this!" He struck the ball harder and it bounced off the teleport, striking the Sontaran in the vent at the back of his neck. He spun around and pushed the soldier, grabbing Rose's hand. "Out! Out! Out!"

They ran for the jeep together, Ross still very confused as to what was happening.

"Left me behind again," Rose scolded her husband.

"Can we be mad at me later?" he asked teasingly.

The leapt into the jeep, speeding away. The Doctor picked up the radio and sighed, hating to act like a soldier again, even if he had to.

"Greyhound Forty to Trap One. Repeat: can you hear me? Over."

There was no answer and Ross frowned. "Why is it not working?"

He glanced at Rose. "Must be the Sontarans. If they can trace that, they can isolate the ATMOS."

"Turn left," the device ordered.

"Try going right," the blonde woman suggested.

"It says left," Ross said blankly.

She shook her head. "I know, but it ain't exactly friendly, yeah? So go right."

He glanced at the Doctor for orders.

"Try it," he nodded. "Rose has exceptional instincts."

Ross tried to move the wheel, but took his hands off when it didn't budge. "I've got no control. It's driving itself. It won't stop."

"And the doors are locked!" Rose announced, yanking on the handle.

The Doctor pointed the sonic screwdriver at the ATMOS. "Argh! It's deadlocked! I can't stop it!"

"Turn left," the device instructed, moving them in that direction.

"The sat-nav's just a box, wired through the whole car," the Doctor observed as they swerved off the road.

"Doesn't help much right now!" Rose shouted.

Ross pointed out the windshield. "We're heading for the river!"

"ATMOS, are you programmed to contradict my orders?" the Time Lord asked, suddenly struck by an idea.

"Confirmed."

"Anything I say, you'll ignore it?" he pressed.

"Confirmed."

"Then drive into the river!" he shouted, ignoring the incredulous looks the other two gave him. "I order you to drive into the river! Do it! Drive into the river!"

The vehicle screeched to a stop just at the edge of the river and, finding the doors not deadlocked, the Doctor opened them and they all ran from the machine.

"Turn right. Left. Left. Right," the device continued.

"Get down!" the Doctor shouted, shielding Rose as Ross dove to the ground.

"Left. Right. Left. Right. Left. Right. Left. Right."

The panel in the car smoked and sparked, but didn't explode. The three looked back after a moment.

"Oh, is that it?" the Doctor asked, surprised and a bit disappointed.

Rose laughed. "I suppose we're walking, eh?"

After trekking their way back toward the way they'd come, they found the house Donna's family lived in and rang the bell. Their friend opened the door, surprised.

"You would not believe the day we're having," the Doctor told her by way of greeting.

Before long he was examining the family car, and the ATMOS that had been installed. Rose was there, but off to the side with Donna while the redhead tried to phone Martha.

"I'll requisition us a vehicle," Ross said, moving off to contact someone.

"Anything without ATMOS. And don't point your gun at people," the Doctor said.

As the young man left, Rose frowned. "What happened to 'Ross is nice, we like Ross'?"

He ducked his head sheepishly. "He's still a soldier."

"Is it him? Is it him? Is it the Doctor?" an elderly man asked excitedly, bursting from the house and running toward the car. He stopped short upon seeing the Doctor. "Ah, it's you!"

"Who?" the Doctor asked, lifting his head and seeing the man. "Oh... it's you! Rose, look!"

She recognized the man they had seen while on the Titanic. "Oh! Hello again!"

"What, have you met before?" Donna asked, mouth hanging open.

Her granddad grinned. "Yeah, Christmas Eve. They disappeared right in front of me."

The redhead looked between her friends and her grandfather, trying to process what she'd just learned. "And you never said?!"

"Well, you never said," the older man shrugged helplessly. He turned and offered the Doctor his hand. "Wilf, sir. Wilfred Mott. You must be one of them aliens."

The Doctor grinned at him, shaking his hand enthusiastically. "Well, yeah, but don't shout it out. Nice to meet you properly, Wilf. And you remember my wife, Rose Tyler?"

"Ah, an alien hand," Wilf grinned back, before turning and inclining his head charmingly at Rose. "Madame, I am honoured."

"I thought you were Wilf," she teased back with a wide smile, delighted when he laughed.

The Doctor turned to his friend. "Donna, anything?"

Donna shook her head. "She's not answering. What's it, 'Sontiruns'?"

"Sontarans. But there's got to be more to it. They can't be just remote-controlling cars. That's not enough. Is anyone answering?"

"Hold on," she frowned, dialing again.

"What else could they be after?" Rose asked thoughtfully. "I remember reading about 'em. They're clones, so they ain't looking for a place to raise the kids; they're all about their wars, and humans ain't much of a fight for 'em."

"You're gorgeous when you're being brilliant," the Doctor teased her.

She stuck her tongue out at him. "So I'm always gorgeous, then."

He was saved from answering by the approach of Donna, who was speaking into the phone. "Martha, hold on, he's here."

She handed the phone over, frowning at Rose. "Figure anything out yet?"

"Working on it," Rose shrugged, half listening to what the Doctor was saying.

"Martha, tell Col Mace it's the Sontarans. They're in the file, Code Red Sontarans. But if they're inside the factory, tell him not to start shooting, UNIT will get massacred. I'll get back as soon as I can. You got that?"

The Doctor went back to poking around at the ATMOS under the bonnet and Wilf joined him there. The women remained a step back, working over the details they already knew… okay, they were kind of comparing childhoods and neighborhoods, but it was close.

"You've tried sonicking it before. You didn't find anything," Donna reminded him after a bit.

"Yeah, but now I know it's Sontaran, I know what I'm looking for," the Doctor replied with certain distraction.

Donna and Rose spoke quietly, while Wilf looked at the Doctor seriously.

"The thing is, Doctor, that Donna is my only grandchild. You gotta promise me you're gonna take care of her," he said quietly.

The Doctor smiled a bit at him. "You've got it backwards, Wilf. She takes care of us."

The older man laughed a bit. "Oh, yeah, that's my Donna. She was always bossing us around even when she was tiny. 'The Little General' we used to call her."

Hearing them, Donna cringed. "Yeah. Don't start."

The Doctor concentrated on a specific part with holes in a grid pattern.

"And some of the boys she used to turn up with - a different one every week. Yeah, who was that one with the nail varnish?"

"Matthew Richards," Donna supplied. "He lives in Kilburn now - with a man."

Rose made a face. "Had one of them. At least none of yours smacked you around and left ya in debt for some other girl."

The Doctor stared at her with a dark expression. "Who did what?"

"Pay attention to what you're doing there, love," she instructed calmly. "This is hardly a good time to talk about someone I dated… what it is… fifteen years ago? Twenty?"

Spikes shot out of the holes in the device, catching all of their attention.

"Whoa! It's a temporal pocket!" the Doctor exclaimed in a way that told Rose he was adequately distracted. "I knew there was something else in there. It's hidden just a second out of sync with real time."

Rose jumped and moved closer to stare curiously.

"But what's it hiding?" Donna asked, moving forward as well.

It was while they were there, all four with their heads under the bonnet that Donna's mother, Sylvia, arrived.

"I dunno, men and their cars! Sometimes I think if I was a car..." She trailed off. "Oh, it's you! Doctor-what was it? And Rose?"

Not one person looked at the woman, but the Doctor waved a hand. "Yeah, that's me."

Wilf reached out to tap on the device. "Have you met him as well?"

Sylvia huffed. "Dad, it's the man from the wedding! When you were laid up with Spanish flu. I'm warning you, last time that man turned up, it was a disaster!"

Rose looked up, scowling. "Hey, if he wasn't around, it'd be a lot worse than a disaster."

Gas shot out, clouding around them.

"Get back!" the Doctor snapped nervously, leaping back and snatching Rose to his side.

She pushed at him. "Can you stop it? We don't know what that is!"

Without releasing her, he pointed the sonic screwdriver at the car, "This'll stop it."

There were a few sparks and the gas stopped pouring out.

"I told you! He's blown up the car! Who is he anyway? What sort of doctor blows up cars?" Sylvia shouted.

"Oh, not now, Mum!" Donna snapped, not wanting to hear anyone say bad things about her friends. She understood now the choices they faced, and she couldn't stand hearing her own mother blame them for things that went far beyond their control.

The older woman scowled, driven by her desire to see her only child safe, and happy… and safe. "Oh, should I make an appointment?"

She stalked away to brood over Donna's obvious choice, leaving the other four to deal with the car.

"That wasn't just exhaust fumes. Some sort of gas. Artificial gas," the Doctor said with a frown.

Wilf looked at him with amazement. "And it's aliens, is it? Aliens?"

"I think it's probably poisonous," the blonde woman said seriously.

The other woman shuddered. "But if it's poisonous... Then they've got poisonous gas in every car on Earth."

They looked around. Every car that could be seen from where they stood proudly showed ATMOS stickers in the windows. Each one a potential threat…

Wilf frowned. "It's not safe. I'm gonna get it off the street."

He got into the car and the memory of what happened in the jeep flooded Rose with dread. "No, don't!"

The door slammed shut and locked as the car started automatically. The gas began pouring out of the tailpipe.

"Turn it off!" Donna shouted, slapping the window as her granddad shook his head helplessly. "Granddad, get out of there!"

She tried the door, crying out in alarm when it wouldn't open.

"I can't! It's locked! It's the aliens again!" he shouted, holding up the key, showing he hadn't be the one to start the car.

Sylvia shouted out to them, "What's he doing? What's he done?"

"I've isolated it!" the Doctor assured them.

"Hurry Doctor," Rose encouraged him. "You know they're gonna be working against you."

"There's gas inside the car! He's gonna choke! Doctor!" Donna sobbed.

He moved around to the door, trying to get it open. He didn't want to see anything happen to someone who had been kind to them, or someone so important to his friend, but it wouldn't budge. "It won't open!"

"It's the whole world," Rose said in growing horror, staring around as every car started and poured out the same noxious gas.

"Help me!" Wilf cried, his voice growing weaker. He coughed and looked at his granddaughter.

The Doctor ran up to the engine and yanked at some wires. In desperation, he turned to Rose, his eyes wide. She looked back, standing in the street as the air became thick with the gas and fumes billowed around her. For once, neither knew what to do.

"Doctor!" Donna cried in desperation. "Rose! Help!"