They walked into the TARDIS, and behind him, Jack heard Ancelyn freeze. The torches were not very bright, but bright enough that the dimensional transcendence of the time ship was obvious. Jack turned. "First time in a TARDIS," he said, sympathetically.
"This is the ship of time?" Ancelyn whispered.
"Larger within than without," the Doctor supplied, and it sounded to Jack vaguely as though he were quoting. "It's good to see that the old girl is still in one piece, at least." He held the torch up, surveying the damage. "More or less," he amended.
"The rotor is damaged," Jack said. "Is that even fixable?"
"Oh, yeah," the Doctor said, with false bravado, "done it plenty of times. Now, let's just see if we can get a decent look 'round." He pulled the sonic screwdriver out of his coat pocket, and pointed it at the torch. The torch flared bright, filling the console room with light. Jack could see now just how badly the ship was damaged. Debris was everywhere, and there were cracks all through the coral struts. The console showed no signs of life.
The Doctor jammed his torch into the floor, and went to the display. It didn't respond to him. He fiddled with the controls, typed on the keys, soniced it, and finally resorted to hitting it. Nothing worked. The Doctor began pulling up floor panels, investigating dead circuitry and power cells. Finally, he threw a panel aside in frustration, leaning his head into one of his hands. "This happened once before," the Doctor said, running his hand through his hair. "With Rose and Mickey. Fell right through the Void into an alternate world. We were very nearly stuck there- the TARDIS lost power, and the energy from that world was on the wrong frequency to let her recharge."
"How did you get out?" Jack asked.
"I found a power cell, and I gave it my own life energy. Since I'm from the same universe as the TARDIS, it could use that. I was hoping I'd find another power cell this time, but there's nothing! And besides, the damage is much worse. The TARDIS could heal itself, but it needs time, and lots of power. But it's barely got enough power to keep it alive right now, much less get us home-" The Doctor broke off, looking into the distance. His eyes narrowed. "That's why I wouldn't wake up," he said, with sudden realization. "She needed me. She was taking energy from me to stay alive!"
Jack was horrified. "She was draining you? But-" he thought for a moment. "How long can she survive without access to a power source?"
"I don't know," said the Doctor, grimly. He pulled himself up and looked at the underside of the console. "No, no, no, no, no..." He started pulling panels open again, feverishly poking at wires and parts. Finally, he stopped, leaning his forehead against the edge of the console. Even in the dim light, Jack could see the Doctor's eyes close. He sat there, still against the console for a long moment.
Suddenly, he popped his head up, and turned to Ancelyn. "D'you have rope?" he asked.
Ancelyn looked confused. "How much rope?" he asked.
"About..." The Doctor held out his arms, starting at the console, and walking sideways out toward the door. "...That much," he said, pointing at the nearest of the horses.
"Doctor, what are you going to do?" asked Jack, suspiciously. He wasn't sure what the Doctor had in mind, but he was reasonably certain that he wasn't going to be happy about it.
"The TARDIS needs energy," the Doctor said, with a wild grin. "And I'm going to give her what she needs."
"Care to elaborate, Doc?" Jack ran his hand over one of the coral struts, wincing at the ugly crack that ran through it.
"D'you remember Blon Fel-Fotch?" the Doctor said. "The Slitheen?"
"Tried to blow up Cardiff, yeah," Jack said. "I lived through that twice, by the way. It was hell to convince my team to stay inside and do nothing during all that."
"Yeah, well," the Doctor said, dismissively. "You remember what happened to old Blon." He waggled his eyebrows, hands in his pockets.
"Of course. The energy from the rift was starting to crack the TARDIS open- along with the rest of the planet, I might add- and the TARDIS zapped her-" Jack suddenly realized what the Doctor intended to do. "You can't be serious, Doctor!"
"I am," he said, in an affronted tone of voice. "We have two problems." He held up a finger. "First, I can't access my link to the TARDIS. And I'm very interested in talking to whoever it was who helped you manage that, by the way, because you apes shouldn't be able to interfere with the Imprimatur." He flicked up a second finger. "And second, the TARDIS doesn't have enough energy to heal itself. This solves both problems. We crack open the console, I look into the heart, she siphons off whatever she needs, and it reestablishes the link. Home in time for tea."
"If it doesn't kill you," Jack said, sarcastically. "Or drive you mad."
"Oh, please," the Doctor said, grinning again. "I've been mad for years."
Jack frowned. "I mean it, Doctor. The last person to look into the heart of the TARDIS was Rose, and it would have killed her, if you hadn't let it kill you first."
"That was because Rose was human," the Doctor said. "She couldn't stop herself from absorbing the Vortex energy, and neither could Blon Fel-Fotch. But I'm not a human or a Slitheen. I'm a Time Lord. I can let the TARDIS have access to me, but not take the Vortex energy into myself. No Vortex energy, no dying."
Jack glared at the Doctor. "Even if you can avoid absorbing the Vortex, you'd be letting her drain your life force. If she takes too much, would you even be able to regenerate?"
"Jack," the Doctor said, his teeth gritted. "Jack, if a friend of yours was going to die, and you had to risk your life- your only life- for even the chance to save them, would you do it?"
"Doctor," Jack said. He didn't continue. He could only think of the moment when he'd done just that, and gladly. Wish I'd never met you, Doctor, I was much better off as a coward.
"She's dying," the Doctor said, helplessly. "She's going to die in the dark, alone and afraid." He looked down for a moment, and then back up. "Help me, Jack."
Jack turned to Ancelyn, who was standing awkwardly off to the side of the console room. "There was a farm nearby, where you got the wagon," he said. "Would they have plow horses we could borrow?"
Some time later, Jack found himself tying rope to a horse collar by torchlight. "You got that end secured, Doctor?" he called into the TARDIS.
There was a clanging noise from inside, followed by a pause. "Not quite!" the Doctor called back. Jack patted the horse's neck, smiling. He wouldn't have thought that tying rope to the console would be a difficult maneuver, but perhaps there were complexities he wasn't aware of.
Ancelyn, standing beside another horse, looked up. "I have finished here as well, Doctor," he called. "'Twill hold fast!"
There was more clanging, and the Doctor appeared, leaning out of the doorway. "Did you know that you can sonic rope?" he asked, grinning madly. He twirled his screwdriver in one hand. "'Cause you can."
"I take it you're ready to go, then," Jack said. He turned to Ancelyn. "Okay- when I give the signal, have the horses start pulling. I'll go inside with the Doctor."
"As you have said it, Sir Jack," Ancelyn said, hands on the horse nearest him.
Jack walked toward the TARDIS. "Are you sure this is a good idea, Doctor?"
"It's the only one I've got," the Doctor answered. "And that's saying something. Alright- you have Ancelyn start the horses going, and I'll trip the controls to release the console." The Doctor wouldn't typically have needed something so blunt-force as plow horses to open the TARDIS console- but with the power out, desperate measures were called for. The Doctor would work the controls, the horses would provide the necessary kinetic energy.
"So," Jack said, walking inside after the Doctor, "we pull the console open, and you look into the heart. What then?"
"I don't know," the Doctor said, with unusual candor. "I suppose we'll find out." He moved to the front of the console, and stood expectantly.
Jack frowned. "Ready, then?" he asked, reluctantly.
"As I'll ever be," he said, quietly. He reached out, and began manipulating the controls on the console.
Jack, standing off to the side, leaned towards the door. "Now!" he called.
The ropes went taut as the animals pulled and strained. For a moment, it seemed as if nothing was happening. Then there began to be a creaking sound. "Keep going!" Jack shouted. The creaking got louder, and louder. The ropes looked as though they might give, but the Doctor buzzed them with the sonic screwdriver again. The TARDIS began to shake, and Jack steadied himself against a strut. In front of him, there was a loud cracking noise. The console opened.
"Stop!" he called to Ancelyn. "Stop!" He turned, and looked toward the console.
When he'd seen the console open before, the light had been brilliant, blinding. It had been as if a tiny star lived inside the TARDIS, and from what Jack understood, that wasn't far wrong. Now, though, it was dim. It seemed to Jack that it had the quality of light at sunset, when the shadows are long and the light glows yellow. Jack tried not to look at it. Instead, he watched the Doctor.
The Doctor walked toward the light, one hand extended. "Shhhh," he whispered, as though to calm a child or a skittish animal. "Oh, I'm sorry. I'm so sorry you were alone. But here I am again. See? I wouldn't leave you." His tone of voice made Jack's breath catch.
The light flared just a little, and the Doctor stared into it, hand still extended. Jack felt uncomfortably as if he were intruding on a private moment.
"Oh, you're beautiful," the Doctor breathed. "Really beautiful. It's alright. I know you're frightened, but I'm here. Come to me."
The light flared again, and tendrils of the light began to creep towards the Doctor. "That's right," the Doctor said, encouragingly. Suddenly, the tendrils snaked out, slamming into the Doctor's mouth and eyes. The Doctor's body jerked twice, his arms falling limp to his sides and his head dropping back. He looked like a puppet, being held up only by the ropes of light going to his face.
"Doctor?" Jack called, alarmed. He had no idea whether this was supposed to happen or not. Inside the console, the light grew brighter.
From the doorway, Jack heard Ancelyn's voice. "Sir Jack!" he called, uncertainly. He approached, skirting the edge of the console room. "Is this what he prepared for?"
"I don't know," said Jack. The Doctor was being lifted up in the air now, the toes of his trainers just barely touching the floor. The light from his eyes and mouth seemed to pulse. The rest of his body was limp and still. The silence in the TARDIS was unnerving. "I'm not sure he knew," Jack said, as much to break the silence as anything.
"Might it indeed kill him?" Ancelyn asked, concerned. "He grows pale."
Ancelyn was right. The Doctor's skin seemed paler in the torchlight than it should. "I don't know!" Jack repeated. They watched in uncertain silence. Suddenly, Jack heard a pling noise, like a drop of fluid hitting metal. Shifting positions, he looked for the source of the noise. Another pling, another drop, and he saw it. There was a trail of blood running from the Doctor's nose, dripping onto the floor. Jack was closer now, and he had a better view of the Doctor. He was so pale as to be translucent, veins and arteries showing through his exposed skin like a road map. As Jack watched, the Doctor shuddered once, splattering more blood onto the floor. "That's it." Jack looked back to Ancelyn. "We have to stop this."
"Dare we pull him away?" Ancelyn asked, edging closer. "I am loathe to interfere with this sorcery," he said, warily.
"I won't just stand here and let him die. We can close the console," Jack said. "Or try." He walked toward the console, careful not to get close to the Doctor. The whole console was lit now, glowing a dim green. Jack reached out and touched it, cautiously. Nothing happened. Experimentally, he pushed down on the top part of the console, where it had been pulled up and out. "Go around the other side," he said to Ancelyn. "On three..."
Ancelyn positioned himself. "One... two... three!" Jack said, and he and the knight pushed with all their might. Nothing happened; the console did not budge. "Again!" Jack cried, leaning into it.
The console did not budge.
Jack stopped, leaning over the console. Motion caught his eye, and he turned to see the Doctor twitch again, his head lolling. As Jack watched, another drop of blood plinged onto the ground. The Doctor was bleeding from the eyes now, body jerked again, and again. Jack felt despair. He bowed his head, both hands gripping the console so hard his knuckles turned white. "Let him go," he begged the TARDIS. "You're killing him. I know you don't mean to. I know you're hungry and afraid, but you have to let him go, or he'll die."
Across from him, he heard Ancelyn's voice. "Look!" he said. "The light- it has stopped moving."
Jack looked up. Ancelyn was right. The pulsing motion that he had perceived in the light before had stopped. His heart leapt. The TARDIS was responding to him. "That's right," he said, excited. "Let him go. I'll take care of him, I promise. You know I will."
Where it contacted the Doctor, the light grew dimmer, more tenuous. The Doctor was lowered to the ground, the heels of his feet hitting the floor. "Let him go, sweetheart," Jack whispered. "Just let him go."
In swift and sudden movement, the tendrils of light snapped away from the Doctor. The console, which had not yielded to their combined strength, pulled shut with an audible snap. The Doctor's head dropped to his chest, and he stood shakily for a long moment. Then he crumpled to the floor.