“I can't believe I'm doing this!” Donna exclaimed.
The Doctor and Lilith stood back watching her as she flew the TARDIS. “No, neither can I,” the Doctor muttered. “Oh, careful.” He hits the console with the rubber mallet and pulled a lever, then let Donna take control again.
“Left hand down,” Lilith instructed. “Getting a bit too close to the 1980s.”
“What am I going to do, put a dent in them?” Donna asked, sarcastically.
“Well, someone did,” the Doctor said.
A phone started ringing. “Hold on. That's a phone.”
The Doctor picked up Martha's old flip phone from a socket in the console. He answered it. “Hello?”
Lilith heard a familiar voice on the other end and squealed with delight. “Martha!”
The Doctor quickly set the coordinates and the TARDIS materialized. He and Lilith stepped out of the ship. “Martha Jones.”
“Doctor,” she greeted. They hugged. “Lilith, good to see you.”
Lilith grinned and hugged her too. “Always a pleasure, Aunt Martha.”
Donna came out of the TARDIS.
“Right. Should have known. Didn't take you long to replace me, then,” Martha said.
“Now, don't start fighting. Martha, Donna. Donna, Martha. Please don't fight. Can't bear fighting.”
“You wish,” Donna snorted. The women shook hands. “I've heard all about you. He talks about you all the time.”
Martha raised her eyebrows. “I dread to think.”
“No, no, no. No, ne says nice things. Good things. Nice things. Really good things.”
“Oh my God. He's told you everything.”
“Didn't take long to get over it though.” Donna noted the ring on Martha’s finger. “Who's the lucky man?”
“What man?” the Doctor asked. “Lucky what?”
“She's engaged, you prawn.”
Lilith frowned. Mickey was still in Pete’s world. “Really? To who?”
“Tom,” Martha answered. “That Tom Milligan. He’s working out in Africa right now.”
The Time Lady cracked a smile. “You mean that doctor we traveled with?”
“Yes, I know, I've got a doctor who disappears off to distant places. Tell me about it.”
“Is he skinny?” Donna questioned.
“No, he's sort of strong.”
The ginger companion jabbed her thumb at the Doctor. “He is too skinny for words. You give him a hug; you get a paper cut.”
“Alien streak of nothing,” Lilith teased.
The Doctor rolled his eyes. “Oh, I'd rather you were fighting.”
“Doctor Jones, report to base, please. Over,” a voice said over a walkie-talkie.
Martha answered it. “This is Doctor Jones. Operation Blue Sky is go, go, go. I repeat, this is a go.” A convoy of jeeps, trucks, and a squad of the Parachute Regiment went past. A car with Army top brass goes past, and they all headed to the ATMOS factory. “Greyhound Six to Trap One. B Section, go, go, go. Search the ground floor. Grid pattern delta,” Martha said.
“What are you searching for?” the Doctor asked.
“Illegal aliens.” She went back to her walkie-talkie. “B section mobilized. E section, F section, on my command.” She ran off to join the troops under her command.
“Is that what you did to her?” Donna said quietly. “Turned her into a soldier?”
Lilith sighed. “Believe me, that was not his intention.”
“And you're qualified now,” the Doctor said, catching up to Martha. “You're a proper doctor.”
“Military doctor, just like I was told.” Martha winked at Lilith. “UNIT rushed it through, given my experience in the field. Here we go. We're establishing a field base on site. They're dying to meet you.”
“Wish I could say the same,” the Doctor muttered. They got into the back of a truck.
UNIT. Well, this was going to get interesting.
“Operation Blue Sky complete, sir,” Martha reported to a higher up. “Thanks for letting me take the lead. And, this is the Doctor. Doctor, Colonel Mace.”
“Sir.” Colonel Mace saluted
The Doctor made a face. “Oh, don't salute.”
“But it's an honor, sir. I've read all the files on you. Technically speaking, you're still on staff. You never resigned.”
“What, you used to work for them?” Donna looked shocked.
The Doctor shrugged. “Yeah, long time ago. Back in the 70's. Or was it the 80's? But it was all a bit more homespun back then.”
“Times have changed, sir.”
“Yeah, that's enough of the sir.”
“Come on, though, Doctor. You've seen it,” Martha said. “You've been on board the Valiant. We've got massive funding from the United Nations, all in the name of Home World Security.”
Mace nodded. “A modern UNIT for the modern world.”
“What, and that means arresting ordinary factory workers, in the streets, in broad daylight? It's more like Guantanamo Bay out there. Donna, by the way. Donna Noble, and this is Lilith Smith, since you didn't ask. We’ll have a salute.”
Mace looked at the Doctor, who gave a sort of nod, so the Colonel saluted the two women. “Ma’am, Collector.”
“Tell me, what's going on in that factory?” the Doctor questioned.
“Yesterday, fifty two people died in identical circumstances, right across the world, in eleven different time zones,” Mace informed him. “Five a.m. in the UK, six a.m. in France, eight a.m. in Moscow, one p.m. in China.”
The Doctor frowned. “You mean they died simultaneously.”
“Exactly. Fifty two deaths at the exact same moment, worldwide.”
“How did they die?”
“They were all inside their cars.”
“They were poisoned,” Martha said. “I checked the biopsies. No toxins. Whatever it is left the system immediately.”
“What have the cars got in common?” asked Lilith.
“Completely different makes. They're all fitted with ATMOS, and that is the ATMOS factory.”
“What's ATMOS?” the Doctor wondered.
Donna scoffed. “Oh, come on. Even I know that. Everyone's got ATMOS.”
“Stands for Atmospheric Omission System,” Martha told the Doctor. “Fit ATMOS in your car, it reduces CO2 emissions to zero.”
“Zero? No carbon, none at all?” Lilith shook her head. “I’m calling bull.”
“And you get sat-nav and twenty quid in shopping vouchers if you introduce a friend,” Donna added. “Bargain.”
“And this is where they make it, Doctor,” Mace said. “Shipping worldwide. Seventeen factories across the globe, but this is the central depot, sending ATMOS to every country on Earth.”
“And you think ATMOS is alien.”
“It's our job to investigate that possibility, Doctor.” The Colonel led them through the factory to a room where the ATMOS device was laid out on a table. “And here it is, laid bare. ATMOS can be threaded through any and every make of car.”
“You must've checked it before it went on sale,” Lilith said.
Martha nodded. “We did. We found nothing. That's why I thought we needed an expert.”
The Doctor put on his specs. “Really? Who'd you get?
Lilith face palmed. “You, Dad. They called you.”
“Oh, right. Me, yes. Good.”
“Okay,” Donna said, “so why would aliens be so keen on cleaning up our atmosphere?”
“A very good question,” the Doctor murmured.
“Maybe they want to help. Get rid of pollution and stuff.”
“Do you know how many cars there are on Earth?” Lilith asked Donna. “Eight hundred million. Imagine that. If you could control every car, you'd have eight hundred million weapons with at least five ways to kill a person.”
“I’m going to go check the office,” Donna decided and left.
The Doctor nodded absently as he and Lilith studied the ATMOS components. "Ionizing nano-membrane carbon dioxide converter. Which means that ATMOS works. Filters the CO2 at a molecular level.”
“We know all that,” Mace said, “but what's its origin? Is it alien?”
Lilith shook her head. “No, but it’s decades ahead of its time.”
The Doctor looked up at Mace. “Look, do you mind? Could you stand back a bit?”
Mace frowned. “Sorry, have I done something wrong?”
“You're carrying a gun. I don't like people with guns hanging around me, all right?”
“If you insist.” Mace left too.
“Tetchy,” Martha noted.
“Well, it's true.”
“He's a good man.”
“People with guns are usually the enemy in my books.”
“Lilith carries a gun,” the human pointed out.
The Doctor didn’t bother to look at her. “I couldn’t get her to give up that thing if I tried."
“And it’s not like he let’s me use it that much, anyway,” Lilith grumbled.
“Besides, look at me,” Martha said. “Am I carrying a gun?”
The Doctor sighed. “Suppose not.”
“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."
Lilith elbowed Martha. “That sounds more like Martha Jones.”
“I learned from the best.”
“Well,” the Doctor said with false modesty.
Mace and Donna came in. Donna was holding an empty folder. “Oi, you lot. All your storm troopers and your sonics. You're rubbish. Should've come with me.”
“Why, where have you been?” the Doctor asked.
“Personnel. That's where the weird stuff's happening, in the paperwork. Because I spent years working as a temp, I can find my way round an office blindfold, and the first thing I noticed is an empty file.”
“Why, what's inside it? Or what's not inside it?”
“Sick days.” She opened the folder. “There aren't any. Hundreds 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.”
Mace took the folder. “That can't be right.”
“You've been checking out the building,” Donna said. “Should've been checking out the workforce.”
Martha grinned. “I can see why he likes you. You are good.”
“Super temp.” Donna preened.
“Doctor Jones, set up a medical post. Start examining the workers. I'll get them sent through,” Mace ordered.
“Come on, Donna. Give me a hand.” Martha and Donna went one way; Mace went the other. The Doctor and Lilith followed the Colonel.
He led them to a room with a large computer screen. “Luke Rattigan. Child genius. Invented the Fountain Six search engine when he was twelve years old. Millionaire overnight. Now runs the Rattigan Academy. A private school, educating students handpicked from all over the world.”
The Doctor looked impressed. “A hothouse for geniuses. Wouldn't mind going there.” He headed out into the main factory.
“I must insist that I accompany you,” Mace said.
“You are not coming with us. I want to talk to this Luke Rattigan, not point a gun at him.”
“It's ten miles outside London. How are you going to get there?”
The Doctor looked at him with what Lilith recognized as the ‘dribbled-on-your-shirt-‘ look. “Well then, get me a jeep.”
“According to the records you travel by TARDIS,” Mace noted.
“Yeah, but if there is a danger of hostile aliens, I think it's best to keep a super-duper time machine away from the front lines.”
The Colonel cocked and eyebrow. “I see. Then you do have weapons, but you choose to keep them hidden. Jenkins?”
A young man came over. “Sir.”
“You will accompany the Doctor and take orders from him,” Mace ordered.
“Yeah, I don't do orders.” The Doctor made a face.
“Any sign of trouble, get Jenkins to declare a Code Red. And good luck, sir, ma’am.” Mace saluted and left.
“I said no salutes,” the Doctor complained.
Lilith smirked. “Now who’s giving orders?”
“Oi! Cheeky. You don’t get that from me.”
Donna approached them. Lilith frowned at the look on her face. “Doctor.”
The Doctor grabbed Donna’s hand and pulled her along. “Oh, just in time. Come on, come on, we're going to the country. Fresh air and geniuses, what more could you ask?”
“I'm not coming with you,” she said. “I've been thinking. I'm sorry. I'm going home.”
The grin slid off the Doctor’s face. “Really?”
“I've got to.”
The Doctor rocked back on his heels. “Oh, if that's what you want. I mean, it's a bit soon. I had so many places I had wanted to take you. The Fifteenth Broken Moon of the Medusa Cascade, the Lightning Skies of Cotter Palluni's World, Diamond Coral Reefs of Kataa Flo Ko. Thank you. Thank you, Donna Noble, it's been brilliant. You've, you've saved my life in so many ways. You're…” Lilith tried, and failed, to suppress a laugh when the penny dropped. “You're just popping home for a visit, that's what you mean.”
Donna nodded with a smirk. “You dumbo.”
“And then you're coming back.”
“Know what you are? A great big outer space dunce.”
The Doctor looked down, ashamed. “Yeah.”
“Ready when you are, sir.” Jenkins called from the car.
“What's more, you can give me a lift. Come on,” Donna said. They got in the Jeep.
Lilith looked at her father, grinning from ear to ear. “The broken moon of what?”
“I know, I know.”
The two women spent the rest of the ride to the Noble household laughing.