By sunrise, Jack and Mickey had made no progress on translating the aliens' messages. Jack sighed and put his wrist unit back on, pushing the laptop away.

"They're just not compatible." He gave Mickey an icy look. "Someone's interface is too primitive."

"Hey," said Mickey defensively. "This is top of the line! It's not my fault if it's not good enough for Buck Rogers."

Rose stood up and sighed. "I'm going to check on the Doctor."

Suddenly, they heard yelling outside. Rose, Jack and Mickey headed for the door.

"Sandra?" Rose recognized the neighbor. "What's going on?"

"He won't listen! It's this light, he just keeps walking."

Rose looked at Jack, who looked deep in concentration. "That's blood control!" he said suddenly. "What blood type is he?"

Sandra shook her head. "Oh, I don't know, A positive?"

Jack dashed over to the balcony, Rose following closely. Mickey hesitated for a moment and followed them, as Sandra continued to pursue her husband to the stairs.

In the street below, there were hundreds of people, just like Jason, leaving their homes.

"Of course!" Jack hit his palm with his fist. "That space probe–you guys were always so concerned about reaching out, telling friendly life forms all about your species. But it turns out, not everything out there's friendly." He looked at Rose. "How much you want to bet there was a blood sample–an A positive blood sample–on that probe?"

Rose blinked. "But what's it mean, blood control? Where are they going?"

"I don't know," said Jack. "They're going wherever the aliens want them to go. It's a control matrix. Whatever the master sample is has the power to control any living thing containing that same chemical make-up within a six Lyclon radius. If they're right above us…" He paused. "That means the entire Earth."

"So how do we stop it?"

"We don't." He shook his head. "There's nothing we can do." He ducked back inside.

Rose and Mickey exchanged glances.

"I really better check on the Doctor," said Rose, stepping away to follow Jack.

"They're going up to the roof," said Mickey, leaning over the balcony. "They're all going up to the roof."

Rose didn't hear the rest. She joined Jack in the Doctor's bedroom doorway.

"How is he?" she asked.

Jack closed his eyes. "He's gone," he whispered.

Rose felt her eyes fill with tears. The Doctor couldn't be gone! He was the Doctor, he was always supposed to be there for them! But this new man, this new Doctor… he had been too weak…

She threw her arms around Jack and sobbed into his chest. Jack held her tight and stroked her hair.

"What are we going to do, Jack?" she whispered into his jumper. "What are we going to do?"

"I don't know," he said quietly, his voice cracking slightly. "I just don't know."

"What's wrong?" Jackie asked, coming into the room.

"He's gone, Mum," Rose sobbed.

"Oh, honey." Jackie placed a hand on Rose's back.

Suddenly, there was a crashing from the living room and the floor shook. The three of them rushed in to see all the windows in the flat had shattered.

"At least we know where the ship is," said Jack dully. As if on cue, his wrist unit chirped. He slapped a button in frustration and silenced it, cursing under his breath.

He crunched across the glass on the floor, heading for the door. Rose, Mickey and Jackie followed him all the way outside. An enormous spaceship hung over the city, big enough to block the sun. Rose felt a chill run down her spine.

Jack stared at it for a few seconds, then he grabbed Rose's arm.

"C'mon, Rose, I can get you away." He began punching buttons on his wrist unit. "My vortex manipulator. We'll go back in time and we won't have to worry about it."

Rose stared at him dumbly. "You're kidding, right? Jack, I'm not leaving my mum and Mickey. Or the Doctor. No one gets left behind, remember? The Doctor would've stayed and fought and that's what I'm going to do."

She turned on her heel and dashed back to the flat. Jack sighed and ran after her.

"Right," she said. "Jack, Mickey, you get the Doctor. Mum, get some food and stuff."

"Why?" asked Jackie. "Where are we going?"

Rose swept her hair out of her eyes. "The TARDIS. It's the only safe place I can think of."

"Why are we going in there?"

"To hide," she muttered.

"Oh, hiding," grunted Jack as he and Mickey backed out of the Doctor's bedroom, carrying the Time Lord's body. "That's a brilliant plan. The TARDIS is a much better hiding place than 1879."

**

Rose heaved a shopping bag full of food onto the floor of the TARDIS, not even bothering to chase after the thermos of tea that rolled out. She leaned against the console and sighed.

"Jack, are you sure you can't–"

"Yeah," he said, flopping onto the jump seat and putting his feet up on the console. "I can land it." He shifted in his seat; his boot hit something on the console computer. "And there aren't even any weapons!"

"What about you?" asked Mickey, grabbing an apple from the shopping bag and taking a bite. "You flew it."

Rose frowned. "Yeah, but I don't… I don't remember. I mean–"

"Don't remember? How come you don't remember? You me and Jackie, we–"

"She says she doesn't remember!" snapped Jack. "And when she says she doesn't remember, you shut up."

"I don't need you to speak for me, Jack," said Rose irritably.

"Hey, I was just trying to help. The world could use a little chivalry."

"Well, you could've fooled me!"

"Just what I need," muttered Mickey. "Trouble in paradise."

"I'm going to go give Mum a hand," said Rose. She stomped to the door of the TARDIS, giving the thermos a good hard kick as she went by. Let Jack and Mickey clean it up if they wanted to be chivalrous.

She wrenched open the door. She only had a split second to register that the TARDIS had somehow moved, when she was grabbed by something huge–one of the aliens. She screamed.

"Rose!" Jack jumped to his feet and bolted for the door, shoving Mickey out of the way. "Rose!" He burst out of the TARDIS and was grabbed by another of the aliens. Mickey was right on his heels.

"Close the door!" she shrieked. Mickey slammed the door before being grabbed by one of the aliens.

Rose flicked her eyes around the interior of the spaceship. It was an enormous room, a cavern, really, full of aliens. The aliens holding her, Jack and Mickey shoved them toward a group of other humans. The aliens were all cheering.

"Rose!" It was Harriet Jones. She rushed over and they embraced. "The Doctor. Is he with you?"

Rose shook her head. "No. It's just us." She looked away, blinking back tears.

One of the aliens started speaking. Rose couldn't understand what it was saying, but it sounded like it was talking about her and Jack. To her left, she vaguely heard one of the men with Harriet Jones translating what it was saying.

"These two. They have the clever blue box. Therefore, they speak for your planet."

"But they can't!" said Harriet Jones.

"Yeah, I can," said Rose, stepping forward.

Jack grabbed her arm. "Like hell you are."

She yanked her arm back. "Let go of me."

He leaned in to whisper in her ear. "Who has experience with hostile negotiations, hm?"

The aliens began to chant.

"They're saying, 'speak, speak,'" said the translator.

Rose and Jack exchanged glances and Jack stepped forward.

"Right." He took a deep breath and rubbed his hands together. "I'm Captain Jack Harkness. That over there, is my ship." He indicated the TARDIS. "Fully armed timeship. Temporal bombs, ion cannons. I have enough firepower to blast you back to the Stone Age–literally." He shoved his hands into his pockets. "So. What do you say you set us down and go on your merry way, or face the wrath of Captain Jack?" He flashed a winning smile.

"What are you doing?" hissed Rose.

"Negotiating," he hissed back.

The alien leader advanced on Jack.

Rose screamed. "Get away from him!"

"'He lies,'" the translator was saying.

"It was worth a try," muttered Jack, watching the circling alien warily.

"'He is unarmed. Your planet is defenseless–'"

"–And he will be the first to die."

"'And he will be the first to die.'"

"No!" screamed Rose, darting forward.

"Your world will be gutted–"

"'Your world will be'–hold on! That's English!"

"Then that means… Then that means…" Rose looked at Jack. He was staring open-mouthed at the TARDIS.

The Doctor was standing there in the doorway, grinning, still in his pajamas and dressing gown. Rose smiled back. Beside her, Jack slumped in relief.

"Thought you'd never get here," he said.

"Well," said the Doctor. "I was a bit under the weather." He easily caught the end of the whip the furious alien leader threw at him. "But I'm feeling all better now." He beamed. "How are you enjoying Old Earth Christmas, Jack? Did Santa bring you everything you wanted? Well, I guess that would require you to have been a good boy this year, when I know for a fact you've–"

The alien charged the Doctor again, this time with a large staff. The Doctor grabbed it and snapped it over his knee, not breaking eye contact with Jack.

"Been somewhat naughty. Now that–" he pointed at the alien "–that was very rude. I was talking to my friend here. Now wait your turn, I'll be with you in a minute." He strode over to where the group of humans was standing.

"Well, look! It's Mickey! And Harriet Jones! Hail, hail, the gang's all here." He turned to Rose and Jack. "It was tea! All I needed was a nice cup of tea. Superheated free radicals and tannins. Heals the synapses just like that!" He snapped his fingers. "Now." He leaned in close to the two of them. "Rose. Serious question. How do I look?"

"Different," said Rose.

"Good different or bad different?"

She shrugged. "Just different."

"That'll do for now. Second question. My ears. Please tell me they're a conventional size."

"Yeah, I guess. They're smaller."

He nodded. "Now, Jack. What do you think of the hair?"

"I love it," said Jack, grinning broadly.

"Brilliant. Second question. Do you realize you put my trousers on back-to-front?"

"Um…"

"No matter." The Doctor waved his hand dismissively. "They'll be off soon enough."

"If I might interrupt!" roared the alien leader.

The Doctor turned. "Oh, right. Sorry. That was quite rude of me." He scratched the back of his head. "I suppose that's the sort of man I am now. Rude. Rude and not ginger. In backwards trousers!" He grinned at Jack and Rose. "I'm going to save the Earth in backwards trousers!"

"I demand to know who you are!"

"I don't know!" the Doctor roared back. Then, he smiled. "That is quite the question, though. See, I'm the Doctor, I know that. Yes, Harriet Jones, the very same Doctor. Just with a different face, unless Rose and Jack are having me on. And that would be quite rude." He shook his head. "But beyond that, I really don't know. I've just got to find these things out by trial-and-error. One time, I'd taken a big bite of peanut brittle before I realized that body was allergic. That wasn't fun. Apparently, I talk a lot. That's one thing. Oh! And another thing!" He sprang up to a large button. "I think I'm curious. Very, very curious in fact. And I think–just a hunch, mind you–that my curiosity is going to lead me to investigate this."

"Doctor, I think that's–" Jack began.

The Doctor shook his head. "No, no, don't tell me, I like to guess these things." He peered at the controls. "So. If I were a–what are you?"

"They're called Sycorax," said Harriet Jones.

"Right. If I were a Sycorax, what would I hide under this great big red button?"

"Blood control," said Jack. "They're using blood control."

The Doctor threw up his hands in exasperation. "Jack! What have I told you! That's why you never get taken to movies, you always spoil the ending." He sighed. "Now that Jack's ruined our little guessing game, it's time for me to…" He slammed his hand down on the button.

"What are you doing?" cried Harriet Jones. Rose winced.

"Saving the Earth!" the Doctor cried. He grinned. "See?" He looked at the shocked faces before him. "Oh, don't look so shocked! It was just blood control. Oh, you tell them, Jack, since you're our resident expert."

Jack turned to Harriet Jones. "Blood control is a simple hypnosis matrix. It can't override the Conatus Circuit. It can't kill. It's good for threats, minor slavery. I'd wager they don't have anything stronger. Doctor?"

The Doctor stuck his hands in the pockets of his dressing gown and strode toward Jack. "Well, I make it a habit not to make bets with time travelers–why is there an apple in my pocket? Jack, this is strange even for you…"

He pitched it over his shoulder. It hit the Sycorax leader in the head. "Oops!" The Doctor put a hand to his mouth. "I seem to have issued a challenge entirely by accident. I guess that makes me a very unlucky man." He shook off his dressing gown and tossed it to Rose.

The Sycorax roared in anger.

"Doctor!" Jack grabbed a sword from one of the aliens guarding them and threw it to the Doctor, who caught it deftly.

"Right then." The Doctor pointed his sword at the Sycorax. "I am this planet's defender. Do you accept my challenge?"

The Sycorax charged. Rose grabbed Jack's hand. The Doctor parried successfully and the fight was on.

Rose didn't think she even breathed the whole time the Doctor and the Sycorax leader were fighting. She wasn't sure where the Doctor had learned how to swordfight, but she was glad he knew how.

The Doctor was able to meet every advance of the alien, despite their great disparity in size. Even when the Doctor was thrown aside, he jumped right up and kept fighting. Rose's heart was beating wildly.

"Is he safe to do this, you think?" she asked Jack. "I mean, just a minute ago, he was dead."

Jack nodded, unable to take his eyes off the scene before him. "I know! Aren't Time Lords amazing?"

The Doctor was guiding the fight up the stairs and out onto the outside deck of the ship

Rose and Jack dashed after him, followed by Mickey and Harriet Jones.

"Doctor!" shouted Rose. "Be careful!"

"Thanks, Rose," said the Doctor, ducking one of the Sycorax's thrusts. "Fighting on the outside of a spaceship parked above London. Guess I'd better be---augh!" The Sycorax leader had cut off the Doctor's hand. Rose watched in horror as it fell over the side of the ship, sword still clutched in it.

"Doctor!" Jack and Rose screamed in unison.

The Sycorax cheered in triumph.

"No," gasped Rose. "No!"

The Doctor smiled serenely. "I thought I was an unlucky man. But I don't think that's true." He raised the stump of his arm. "Because I'm still within the first fifteen hours of my regeneration cycle. Lucky me." Rose watched in disbelief as the hand grew back.

Beside her, Jack whooped. "I love Time Lords!"

Rose grabbed another sword from one of the astonished Sycorax standing on the deck. "Doctor! Catch!"

He caught it in his new hand. "Now I've got both of them throwing sharp, pointy objects at me," he remarked.

The Sycorax leader charged once more and the fight resumed. Rose continued watching in trepidation but her mood was substantially lightened.

After what seemed like eons, the Doctor overpowered the alien and jammed the handle of his sword into the Sycorax's stomach and knocked him to the ground. He held the blade of his sword to his opponent's throat.

He was speaking to the alien in a low voice. Rose couldn't hear what they were saying, but her heart was in her throat. Finally, the Doctor stepped back, thrust his sword into the ground, and looked at Jack and Rose.

They ran towards him. Jack clapped him on the back and Rose helped him put his dressing gown back on.

"See," said the Doctor, putting his arms around their shoulders. "I could do it. Even with my trousers on backwards, and a–what's this, a satsuma?–in my pocket."

"Oh, that'll be Mum's friend's," said Rose. "That's his dressing gown."

The Doctor shrugged. "Your mum's got funny taste in friends." He tossed the satsuma away. It bounced off a button on the side of the spaceship.

Rose turned. The Sycorax leader was plummeting toward Earth, sword in hand.

The Doctor put his arm back around her shoulders. "That was quite rude of him," he said absently. "I don't hold with rudeness."

Once back inside, the Doctor made the Sycorax formally promise not to return to Earth.

"Do you think they'll listen to him?" Mickey asked.

"Oh, they'll listen to him," said Rose, as the Doctor finished his speech.

"When you talk of the Earth, then make sure that you tell them this:" He enunciated every word. "It. Is. Defended."

The next thing Rose knew, they were back where they had come from, outside the Powell Estate.

She blinked.

"We did it!" Mickey cried. "Look!" He pointed. There was a thunderous noise from up above as the Sycorax ship flew away.

Jack grabbed Rose and spun her around. "Couldn't have done it without me," he reminded her.

"Sure, timeship captain," she said, giving him a kiss on the cheek.

"Rose!" It was Jackie.

"Mum!" Rose ran to her mother and hugged her.

"Oh, I knew you could do it. And the Doctor? He's all right? It's really him?"

Rose grinned. "It's really him. All he needed was a good cup of tea."

The Doctor strode over to join them and gave Jackie a hug. Jack, Rose and Mickey joined them.

"I'm glad you're all better," said Jackie.

The Doctor grinned. "I thought I'd never hear you say that."

"Oh, come on, now!"

Jack grinned. "It's because of the new hair, isn't it?"

The Doctor pretended to look offended. "Oh, now, Jack, you're just jealous!"

Suddenly, a bolt of green light shot out of the ground somewhere off in the distance. Three more bolts from different locations joined it, uniting into an enormous laser, which shot into the sky. A few seconds later, there was an explosion somewhere miles above their heads.

"What was that?" cried Rose.

"Don't tell me…" muttered Jack.

"That was murder," said the Doctor harshly.

"That was defense," said Harriet Jones coolly. "It's adapted from alien technology. A ship that fell to Earth ten years ago."

"But they were leaving."

Rose listened to the exchange. She could hardly believe this was the same Harriet Jones. The woman she and the Doctor had met before had been a kind woman, but the prime minister was ruthless and cold.

She leaned over to Jack. "Do you know anything about this time in history?" she whispered.

"Not much," he replied. "I knew the twenty-first century was when Earth first made contact with other civilizations. But I had no idea it happened like this."

The Doctor whispered something to Harriet Jones's translator, and then turned to rejoin the others. He walked off, between Jack and Rose, not looking back.

**

"No, no, no, you know I hate those!" Jack pulled his plate back as Rose came at him with a spoonful of sprouts. Rose, Jack, Mickey and Jackie were sitting down to Christmas dinner. The Doctor had said there was something he needed to do in the TARDIS and that he would join them later.

"Oh, but, Captain, they're good for you," said Jackie. "Give you big muscles."

Jack flexed his arm to show her he already had them.

"Oh, come on," said Mickey. "We're trying to eat here."

The door to the flat opened and they all turned to look. It was the Doctor, but he had changed his clothes–he was now wearing a brown suit.

"New outfit," remarked Rose.

The Doctor smiled and went to sit down between them. "New Doctor."

Jack grinned. "I like a man in a suit."

"Good to know," said the Doctor. "Now, let's have some sprouts! I love sprouts!"

Jack made a face.

"Come on!" said the Doctor, putting some on his plate. "No party hat for Captain Jack unless he eats his veggies!"

"I'm glad you're back," said Rose quietly, as Jack choked down his sprouts.

The Doctor smiled at her and squeezed her hand under the table. "Even if I've got a new body?"

She smiled back. "I think we'll get used to it."

"There." Jack set his fork down. "Happy?"

"Ecstatic." The Doctor reached for a cracker to pull with him. "Green really is your color, you know."

Rose laughed and adjusted her own hat.

The phone rang and Jackie went to answer it. Rose glanced up at the TV. "It's Harriet Jones!" she exclaimed.

Wordlessly, the Doctor stood up and moved closer to the television. He pulled a pair of glasses out of his pocket and slipped them on. Rose and Jack joined him. The Prime Minister was being questioned by reporters–something about rumors regarding the ill state of her health.

"Why are they asking her all those questions?" Rose asked.

"What did you say to her?" Jack asked.

The Doctor didn't say anything.

Jackie returned from the kitchen. "It's Beth," she said. "She says go and look outside."

The five of them headed outside. It was snowing.

"Oh, look," said Rose, pointing. "Meteors?" She looked at the Doctor and Jack.

"It's the ship breaking up," said Jack, putting his hands in the back pockets of his jeans.

"This isn't snow," added the Doctor. "It's ash."

Rose's face fell.

"I told you this was when everything changed," said Jack. "I guess today was that day."

The Doctor sighed. "New Doctor, new world."

Rose stepped closer to the other two and linked arms with them. "It just seems so different."

The Doctor shrugged. "Change is the spice of life. Change is what gets mankind out to the stars! Change is fun, change is terrifying. Change… Change is what powers the universe."

Rose looked back up at the sky. "I just hope it doesn't all change too fast, you know."

"Well," said the Doctor turning to look at her. "Not everything's changed. Mickey's still Mickey. You're still you. Jack's still Jack."

"And you're still the Doctor."

"Exactly."

The three of them looked back up at the sky.

"And I'll take you two someplace where it really is snow."