Rose opened her eyes. Her head was aching badly, but she couldn't tell if it was from lying on the floor of the TARDIS or from… something else. What was the last thing she remembered? Had she… could she have gone home? No, she was in the TARDIS. She remembered the Daleks, but everything seemed all right now; she heard voices, the Doctor's and Jack's, talking quietly.

Jack!

She sat bolt upright. He was right there, leaning against the console, watching as the Doctor fiddled with the controls.

"Jack!" she cried. "You're alive!" The two men immediately stopped talking.

Jack grinned. "Last time I checked–whoa, watch out!" He caught Rose as she stumbled and helped her to her feet. She flung her arms around him and buried her face in his chest.

"I thought we'd lost you," she whispered.

"Nope," said Jack, pressing a kiss to her hair. "I'm right here, alive as ever."

"What happened?"

Jack and the Doctor exchanged glances.

"You don't remember?" asked the Doctor tentatively. He seemed slightly distracted. His eyes flicked to the back of his hand.

"No," said Rose honestly, scratching her head. "I just… it seemed like… no, it's nothing." She waved a hand dismissively. "I'm just glad we got out of there. Are you all right?"

"Me?" The Doctor grinned. "I'm fantastic!"

Rose giggled. "That's great. So where are we going next?" She slid one arm around Jack's waist and the other around the Doctor's.

"I'm up for anything," said Jack. "Just as long as I never hear the word 'exterminate' again."

"There's got to be somewhere you want to go," said Rose. "You've been lots of places, too, haven't you?"

Jack smirked. "Yeah, but I've been a lot of places I'm not allowed back."

Rose laughed. "You're kidding. What did you do, like, kill the Gurg emperor or something?"

"Noo, but I did–Doctor?"

Rose whipped around. The Doctor had stumbled back, obviously in pain.

"Doctor? Are you all right?" Rose and Jack dashed forward.

"Get back!" he shouted. Then he winced.

"Doctor, tell us what's happening! What's wrong?" Rose looked frantically at Jack. "Do you know what's wrong with him?"

Jack shook his head. "I never learned anything about Time Lord physiology. No need to, they were all supposed to be gone."

The Doctor winced. "This is normal." He swallowed hard. "Time Lord's way of cheating death." He gave Jack a significant glance. "It's killing me," was all he said.

"No!" cried Rose. "Jack, we've got to do something! Come on!"

"Rose." The Doctor looked seriously at them. "Jack. This is normal. The thing is… I'm going to look different." He winced. "Different look, same Doctor." He smiled weakly. "See you in a minute." He gave one last jolt before exploding into light.

"Doctor!" shrieked Rose. She started toward him, but Jack grabbed her shoulder, pulling her back. He was watching raptly, but Rose had to look away, burying her face in the fabric of Jack's T-shirt.

After what seemed to Rose like an eternity, she looked. A stranger was standing there, grinning.

"Well, hello!" he chirped. Rose and Jack stepped tentatively toward him. He made a face. "New teeth. That's weird. Right." He looked at Jack. "So. What exactly did you do to the Gurg emperor?"

Then he collapsed.

"Doctor!" Rose dropped next to him. "Doctor, can you hear me?"

"Peanut sat on a railway track, its heart was all a-flutter! Train came rolling down the track, toot toot, peanut butter!" he sang. He burst out laughing and his head lolled to the side.

Rose shook him. "Where's the Doctor, what have you done with him?"

"Rose, I think that is the Doctor," said Jack, crouching on the stranger's other side.

"Right in one, Captain," the man slurred. "Give that man a medal!"

"But… he can't be! That's not the Doctor, he's not our Doctor!" She looked down at the man lying in front of her. "He's got all this… hair."

"Oh, have I got hair?" The man grinned. "At least I'm not bald." He looked at Jack. "Am I ginger? Please say I'm ginger, I've always wanted to be ginger. Do you go in for ginger blokes?"

Jack looked at Rose in bewilderment.

"Oh, my head." The man put a hand to his temple and tried to sit up, slumping against Rose. "Oh, this is nice." He pressed his face between her breasts. "I still fit!"

Rose shoved him back in alarm. "What are you doing?"

"Oh, I've got an interestingly-shaped face, I think I like it. What do you think, Jack? Jack Jack Jackity Jack, oh, I like this tongue!" He stuck it out and leaned toward Jack as if to kiss him. Jack slid back across the floor of the TARDIS.

"Doctor, are you still in there?" Rose called. "We're going to get you some help."

He turned to look at Rose. "Stop all that yelling, I can hear you just fine. It doesn't help the headache. Oh!" A stream of golden energy escaped his mouth. "Oh dear." He collapsed again.

Rose looked at Jack. "Is he…?"

Jack tentatively touched his neck. "He has pulses," he said.

"Can you land this thing?"

"I can try." Jack got to his feet.

"So… if that's the Doctor… d'you really think it's the Doctor?" Rose joined him at the controls.

Jack hit some buttons. "It… might be. Seems to be. He tried to kiss me," he added, as if this was reason to trust the stranger.

The TARDIS lurched and the Doctor's unconscious body slid across the floor.

"If he really is the Doctor…" said Rose thoughtfully, but she was cut off by the jerking of the TARDIS as it dropped out of the Time Vortex.

"At least we're somewhere," said Jack, jerking a lever back in a vain attempt to control the TARDIS's trajectory. "Am I a good pilot, or what?"

The TARDIS hit the ground with a thud. He went sprawling over the control panel and Rose sat down hard. Everything was still.

"You okay?" asked Jack.

"Yeah," said Rose, taking the hand he offered to help her up.

Someone was pounding on the door of the TARDIS. "Rose? Are you in there?"

"Mum?" Rose ran to the door and wrenched it open. "Oh, Mum, it's so good to see you!" Jackie engulfed Rose in a crushing hug.

"Oh, I knew you could do it," she said. "I knew you were alive."

"Could do what?" asked Rose, but her question went unanswered as Mickey moved in for a hug and Jackie noticed Jack.

"Who's that?" she asked.

"Captain Jack Harkness," said Jack. He raised an eyebrow. "You must be Rose's sister. You can't possibly be her mother."

"Jack!" snapped Rose. "Now is not the time."

"I like him," her mother whispered. "American, and that chin. I could die for that chin."

"Ooh." The Doctor dragged himself to his feet, leaning on the railing. "Jack, meet Jackie, Jackie, Jack. Ooh, that's confusing." He shook his head back and forth. "Jack, Jackier, Jackiest."

"Who's that?" asked Jackie.

"Where's the Doctor?" asked Mickey.

Rose pinched the bridge of her nose. "That is the Doctor."

Jackie looked at him curiously. "Are you sure?"

"Pretty much, yeah."

The Doctor was beginning to slide back to the floor again, his eyelids fluttering. "G'night… all of you Jacks."

"Come on," said Rose. "Let's get him inside."

**

Together, Jack and Mickey managed to carry the Doctor into the spare bedroom of the Tylers' flat.

"I'm worried about him, Mum," Rose confided, as Jack wrestled longer limbs than he was used to into a pair of striped pajamas. (Rose wasn't even going to ask why her mother had men's pajamas lying about.) "All those times he's taken care of me–of us–and I don't know how to take care of him."

Jackie put a reassuring arm around her daughter. "We'll think of something. Call Mickey to come back with the car, we'll take him to hospital."

"No!" protested Rose. "We can't. He isn't human, he's got two hearts! They won't know what to make of him; they'll sell him to some lab or something." She was remembering Van Statten.

"But how will we know he's all right?"

Rose wondered why her mother was so concerned about the Doctor; she'd seemed to hate him the last time they'd met. She wondered what had happened to change her mind.

"If only I had some stuff," she said. "Like a stethoscope or something. Then we'd at least know if his hearts were beating."

"I'll see what I can do." Jackie left the room.

"You know, it's much easier getting clothes off him than getting them on," muttered Jack, as he forced the Doctor's hand through the arm of the pajamas.

Rose didn't say anything. Jack came over to her and pulled her into a hug. "Don't worry." He pressed a kiss to her temple. "We're doing the best we can."

Rose relaxed a little. "I know," she said quietly. "I'd just… I'd just hate it if we made it off that awful game station and lost him here."

Jack stroked her hair. "We won't."

"Here, I'm back," Jackie appeared beside them. "Look what I've got." She handed Rose a stethoscope. "Tina's got this lodger, a medical student..."

Rose sat on the edge of the bed and put the stethoscope to her ears, tuning her mother out.

"He's never done this before?" Jackie asked Jack. "How did he change his face?"

"No clue," said Jack. "They never covered this at the Academy. Other species, yeah, but not Time Lords."

"They're both beating," said Rose, standing up.

Jackie made a face; she still didn't seem to grasp the concept of having two hearts. "Are you two hungry? I'll go and get something."

Jack and Rose followed her to the kitchen.

"I'd forgotten it was Christmas," said Rose thoughtfully. "Hang on, what's that on the telly?"

"Oh, didn't you hear? They're launching a space probe." Jackie set three glasses on the counter. "I say, you could tell them a thing or two, don't need to send up a space probe." She filled the glasses with juice.

"Why's Harriet Jones there?"

"She's Prime Minister now," said Jackie, taking a sip of juice. "They're calling it Britain's Golden Age."

"Who's Harriet Jones?" asked Jack.

"We told you about her," said Rose, handing him a glass. "Stopped the Slitheen from destroying the Earth. The first time, I mean."

Jackie paled. "You mean they tried a second time?"

**

Rose had to admit that she felt much better after she had had something to eat, a shower and a change of clothes. She and Jack were watching coverage of the Guinevere One probe when Mickey came over to invite Rose out shopping.

"Can't do anything else for the Doctor," Mickey pointed out.

Rose frowned. "But I don't like leaving him."

"Your mum'll be here. Come on, Rose, I never get to see you anymore."

She looked at Jack. He shrugged. "I've always wanted to see twenty-first century London. Should be fun! Might distract us."

Rose hesitated. "Well…"

"Pretty please… with sugar on top?"

Rose grinned. "Fine, let's go." She grabbed her coat.

"How come you give in to him but not me?" muttered Mickey as they headed out the door.

**

The sights and sounds of Christmas in London were almost enough to take Rose's mind off the Doctor's situation. Almost.

Jack, on the other hand, seemed fascinated. "I've always wanted to see an Old Earth Christmas. I love that old-fashioned stuff," he said, indicating an inflatable snow globe, inside which Rudolph, Frosty and Santa danced to a tinny rendition of Jingle Bells, barely audible over the whirring of the decoration's mechanism.

Rose hid a smile. "He's so cute."

Mickey scowled, as Jack moved on to a couple of mannequins dressed in skimpy Mr.-and-Mrs.-Claus-themed costumes. "What's the deal with him, anyway?"

"I thought you liked him," said Rose. "You two got on fine when we were stopped in Cardiff."

"Yeah, but I didn't realize he was sticking around. It's getting a little crowded in there, isn't it?"

Rose smirked. "Oh, I don't know. It is bigger on the inside…"

Mickey sighed. "Come on, Rose. It's Christmas. Can't it just be you and me on Christmas? Worry about aliens and monsters some other day."

"Okay. I'm sorry, Mickey. I'm just… worried, is all." She took his hand. "Right. Christmas shopping. Mum first?"

Mickey turned. "First, I think you better tell Captain Innuendo that that doesn't count as money."

Rose gasped. "Oh no! Jack!" She dropped Mickey's hand and tore into the shop. "Jack, put those back, we can't buy them!"

**

"Look," said Rose as they exited the shop. "I'll borrow some money from Mickey and buy you something else. Those were just too expensive."

Jack pretended to pout. "You're ruining my first–"

"Look!" Rose pointed across the square. The band of costumed Santa Clauses had lowered their trumpets. Suddenly, flames erupted from the instruments.

"Get back!" cried Jack, yanking Rose back into the alcove. Instinctively, he reached for his sidearm, but it wasn't there. He cursed.

"What are they?" cried Rose.

"I don't know, but we've got to get out of here. Where's Mickey?"

"I'm right here," he said, stumbling up to them. "It's you two, it's got to be you two. Nothing ever tries to kill me if I'm out with my mate Stan."

**

"Mum!" Rose cried as the three of them burst into the flat.

Jackie gave them a look and went back to her phone conversation. "Sorry, Bev, that's her just now. No manners at all! She comes crashing in here, messing up the place…" Jack ran into the Doctor's room.

"Mum, get off the phone," insisted Rose. "It's the Doctor."

"He's fine," Jackie hissed. "In there!"

"No, Mum, get off the phone."

"It's only Bev!"

Rose grabbed the phone. "Sorry, Bev, she'll call you back." She tossed the phone onto the couch and marched after Jack.

"We've got to move him," said Rose quickly, joining him on the edge of the bed. "They're after him, they've got to be. Do you have any idea what they are?"

Jack shook his head. "No, but they were wearing masks."

"But do you know anything like it? Anything with flamethrowers in musical instruments?"

He crossed his arms over his chest. "Something that adapts to its environment. They see it's Christmas, so they become something that'll blend in."

"But we still have to move him!"

"What are you talking about? What's going on?" asked Jackie.

Rose and Jack looked up. Rose opened her mouth to explain but she was cut off by a yell from the living room.

"Mickey!"

Rose, Jack and Jackie tore into the living room, where Mickey was holding a chair to his chest in defense against the Christmas tree which was advancing toward him.

Jackie screamed.

"Get back!" barked Jack. "Get back in there." He shoved Rose back toward the door of the bedroom.

Rose raced to the Doctor's bedside.

"We've got to get out of here," said her mother frantically.

"I'm not leaving him," Rose snapped back.

Outside, Jack and Mickey were rapidly retreating into the bedroom. Rose reached for the Doctor's jacket, which Jack had tossed onto a chair in the corner. She slid the sonic screwdriver out of the pocket and looked at it. If only she knew how to use it… or the Doctor was awake. She slipped it into the sleeping man's hand.

Jack slammed the bedroom door. "It keeps coming. I can't stop it. Damn!"

"Get the wardrobe!" shouted Jackie. In the corridor, Rose could hear breaking glass as the tree made its way toward the room.

The tree began to smash through the door. Jack and Mickey tried to push the heavy wardrobe across the floor.

Rose leaned down to the Doctor's ear. "We need you," she whispered.

The Doctor sat bolt upright and pointed the sonic screwdriver at the Christmas tree. It exploded in a shower of sparks.

"Remote control. But who's controlling it?" he muttered. He climbed out of bed.

Jack slid to the ground in relief. He was breathing hard. Rose was beginning to keenly feel that they had been going for a long time with no rest. She helped Jack to his feet and gave his hand a squeeze.

"He's okay, see?" she whispered. Jack nodded, and they followed the Doctor outside.

He was standing on the balcony, looking down to the street where the four Santas were standing.

"What are they?" asked Jack. Jackie and Mickey joined them on the balcony.

Slowly, the Doctor pointed the sonic screwdriver at the Santas. They backed away warily and disappeared.

"They're gone," said Mickey.

"Teleport," muttered Jack.

"They're pilot fish," said the Doctor, looking at Jack and Rose for the first time. He gave them a weak smile, before coughing and falling back against the wall.

"Doctor!" cried Rose. Jack slid in to catch him and eased him to the ground. Rose knelt at his other side.

"What's wrong with him?" asked Jackie.

The Doctor took in a gulp of air. "Too soon," he panted. "Woke up too soon. The regeneration cycle… it's not… finished yet." He coughed again and more of the golden light Rose had noticed him coughing up in the TARDIS escaped.

He groaned in pain and his head fell against Rose's shoulder. "The pilot fish zero in on the energy in my body. Time Lord regenerative energy's powerful stuff." He closed his eyes, wincing in pain and lurched back against Jack's shoulder, panting. "Very valuable."

Jack put an arm around the Doctor's shoulders to support him. "Is there anything we can do?"

The Doctor took a deep breath. Rose took his hand and squeezed it gently. His other hand flopped against Jack's denim-clad knee.

"Something's coming," he whispered. He swallowed hard, obviously finding it difficult to talk, but knowing he had to tell Jack and Rose what to do. "If they're sending Pilot Fish, they must be close. They're coming after me. Just let me rest." He shivered, his face contorted with what looked like impossible pain. "All I can tell you is let me rest. When they come… I need to be a ready as possible." He closed his eyes and slumped forward.

**

"Just help me tuck him in," whispered Rose, as Jack eased the Doctor back into bed. "He's getting feverish."

Jack helped her slide the blanket up to the restless Doctor's shoulders. Rose sat on the edge of the bed and pressed a hand to his forehead.

"He's burning up," she said mournfully.

Jack sat slowly on the Doctor's other side. "He was awake," he said quietly. "He was fine."

"He's worse than ever now," Rose whispered, choking back a sob.

Jack put an arm around her shoulders. "He'll make it," he murmured. "He always does."

Rose nodded and reached for the stethoscope. "I just want to take a listen."

Jack slid out of the way and Rose pressed the stethoscope to the Doctor's chest, first the right side and then the left. "Only one beating," she whispered, looking up at Jack with tears in her eyes. He hugged her tightly.

Jack and Rose stayed with the Doctor, in the hopes that their familiar presences would help him heal. Suddenly, Jackie gave a cry from the other room.

Jack and Rose jumped up and hurried into the living room.

"Right there!" said Jackie. "On the TV! It was an alien. That space probe took a picture of an alien!"

Rose studied the image on the screen behind the newsreader. "Do you know what that is?" she asked Jack.

He shook his head. "I don't know. But that doesn't mean anything. I do know he's not someone I'd invite home to meet the family."

"Rose. Jack. Look." Mickey indicated his computer screen. Rose and Jack went to stand behind him.

"Military tracking. Mickey Smith, I could kiss you." Jack leaned around him and tapped a few keys. Mickey slid out of his seat and Jack sat down. "Radar. Look, they're tracking something. Something big." He tapped his wrist unit and gave a low whistle. "Whatever it is, it's close."

"How close?" asked Mickey.

He looked at his wrist again. "ETA five-and-a-half hours, give or take a minute."

The image on Mickey's laptop flickered and four of the aliens came into view and began to speak a strange guttural language.

"They must have initiated communications," Jack continued. "Twenty-first century Earth couldn't do that." He furiously tapped keys on Mickey's laptop. "Do you get translation on this thing? Is that what this Alt is for?"

Rose leaned in. "The TARDIS should be translating for us, shouldn't it?"

Jack sighed and rested his forehead on his hands. "It's the Doctor. He's part of the circuit. The translation's the first thing to go if he's not okay."