The Doctor's bushy silver eyebrows knit as he looked at the screen. "We've got company."

Clara whipped around. "What kind of company? Daleks? Cybermen?"

The Doctor clicked a few buttons on the TARDIS's console and narrowed his eyes at the screen. "Neither. Looks like another TARDIS."

"Another TARDIS?" Clara asked as she approached the Doctor, her eyes wide.

"Well I'm not the only Time Lord anymore, Clara," the Doctor said. "Naturally, there's bound to be more than one TARDIS."

"Well whose could it be?" Clara asked.

Before the Doctor could answer, a female voice boomed through the TARDIS console room, as if being broadcasted from all around.

"Attention Doctor," the voice said. "This is the Rani. Surrender yourself or you will be taken by force. You have one minute to comply."

The Doctor's brow furrowed as his face took on a sour edge.

"Who's the Rani?" Clara asked.

"You're full of questions today," the Doctor remarked. "She's a Time Lord like me – well, technically Time Lady. Obsessed with science and experimentation."

"Never heard of her," Clara said.

"I'm sure I've mentioned her before."

"Never."

"Really? Well you must've forgotten. Your memory's not what it used to be."

"So what are we going to do?" Clara asked, ignoring that last remark.

The Doctor buttoned the top button on his dark coat. "Well if she wants me, she's going to have to work for it."

He gripped a lever. "Hold on."

He pushed it forward and the whole TARDIS rocked about. Clara clutched at the edge of the console as the vessel lurched forward at full speed. The Doctor kept his gaze locked on the screen, his wrinkled hands frantically flipping switches and clicking buttons.

"She seems to be locked onto us," he said as the TARDIS made a sharp right turn. "Don't know if we'll be able to shake her."

"Can't we just time travel?" Clara asked. "Like, escape to 15th century France or something?"

"It wouldn't do any good. She's got a time machine, too. She could just track our temporal signal and follow us."

Suddenly, a familiar groaning sound grazed Clara's ears: the TARDIS's trademark materialization noise. Only it sounded more distant and faded. She glanced up at the glowing glass pillar in the center of the console, but it was not moving, indicating that they were not travelling through time.

She turned her attention to the Doctor and realized that the noise was coming from him. The Time Lord looked at his hands in wide-eyed confused as his entire form flickered in and out with every wheezing groan.

Within a few seconds, he flickered out completely, leaving Clara alone in the console room.

Clara looked at the spot where the Doctor once stood, in horror and confusion, and uttered, "What the hell?"

The Doctor faded from his console room and found himself in an area just as spacious as the one he was just in. The entire room was dull grey and stone-like, and was bathed in a soft purple light. An arrangement of daises was set up around the room, upon which sat different rock and mineral samples. In the center was a console much like his TARDIS's, only it had shiny bumps running around the edge and a spiral-shaped center pillar.

The Doctor looked around the familiar-looking console room. "I can see you haven't redecorated after all these years."

"Why would I?" said a cold voice behind him.

The Doctor turned around and saw a dark-haired woman standing inside an arched doorway. She had high cheekbones and was dressed in a dark lavender coat with a red shirt underneath. Her cold, reptilian eyes mechanically scanned the Doctor as she sauntered towards him.

"Teleportation ray?" the Doctor asked.

"Not quite," the Rani answered. "I modified my TARDIS to lock onto your DNA to materialize you out of your TARDIS and into mine. So you could say, hardware wise, I've redecorated quite a bit."

She raised her hand, her middle finger touching her thumb. "Want to see what else I've done?"

She snapped her fingers and a small puffing noise sounded near the Doctor's head. He inhaled an unknown yellow gas and his head started swimming. The room turned black and the Doctor collapsed onto the ground.

The Doctor opened his eyes to a bright light above him. He tried to move his arms, but they were bound to the table he was laying on. He wiggled his legs and his head, but they were also incapacitated. He felt pressure on his face, appendages, and chest, and soon realized that there were wires attached to certain spots on his body.

A form walked into the Doctor's limited field of vision and looked down at him.

"You're awake," the Rani cooed. "Good. Now the procedure can begin."

"What procedure?" the Doctor asked. "What do you want from me?"

The Rani stalked around the table. "As you know, I've been trying to unlock further untapped potential and secrets of the Time Lord regeneration process. But each time, I have been able to discover nothing of use. I've recently been toying around with the possibility of altering the regeneration process so that it could be consciously controlled. If my experimentation is successful, I should be able to regenerate by body into any form I wish, from any future incarnation…or past one."

"That's madness!" the Doctor spat. "That would be impossible to accomplish!"

The Rani walked off to the side, out of the Doctor's vision. "Well, we're about to see."

She clicked something, and the wires attached to the Doctor hummed to life. The captive Time Lord was struck with immense pain, causing him to writhe around on the table and grit his teeth to fight back a scream. His body filled with heat, then cold. The source of the pain shifted from his chest to his head and then to his arms and legs. He felt his insides twist, churn, and crack, his vision becoming bleary and spotty. The light above him seemed brighter than it should have been, and for a moment the entire world took on a golden hue.

Then, the Doctor heard a noise that brought a smile to his face (as big a smile he could muster through all his pain): a groaning, wheezing noise. The TARDIS materialized a few meters from the table, and Clara burst from the door.

"How did you get in here?" the Rani cried as she marched towards Clara. "I will not let you stop the—"

Clara shut her up with a jab to her face, and the Rani crumpled to the floor. The Doctor's companion ran to his side and ripped the wires out from his body. The immense pain stopped, but the Doctor's insides still felt broken.

"Telepathic interface?" the Doctor asked as Clara went to work on his restraints. His Scottish voice sounded ragged with pain.

"Yep," Clara said, undoing his hands. "I just thought of you and the TARDIS brought me here."

"Where'd you learn to fight like that?" the Doctor asked.

"I've been taking self-defense classes on the weekend. My free time doesn't revolve around you."

After she had finished with all of his restraints, Clara helped the Doctor to his feet, but he still needed to lean on her to stay upright. She threw an arm over his shoulder and helped him limp into the TARDIS.

Clara closed the door and the Doctor crashed into the console, clutching at his chest. He frantically clicked some buttons and pulled on a lever, and the TARDIS started groaning and wheezing. The center column rose and fell as the time machine dematerialized.

"Where are we going, Doctor?" Clara asked.

"I don't know," the Doctor gasped. "But it's better than here."

"Won't she catch up to us eventually?"

"Most likely." The Doctor grit his teeth in agony. "But it'll at least buy us some time."

He collapsed to the floor, and Clara ran over to him, crying his name. he held up a hand before she could reach him and sat up. Strangely enough, the pain rapidly started to decrease in his body.

"You know, I'm actually feeling a lot better now," the Doctor said, managing a smile.

But Clara continued to stare at him in wide-eyed horror. "Doctor…you're….you're…"

The Doctor looked at his hands: they were glowing with a golden light. The glow increased by the second and was starting to spread over his whole body.

"I'm regenerating," the Doctor said, standing up.

Tears formed in Clara's eyes. "No, no you can't do this. Not now."

"Looks like it," the Doctor said as his face was enveloped in light. "See you in the next life."

Clara was expecting an explosive regeneration, light shooting out of the Doctor's clothes in long beams. But instead, the regeneration was over in a short, brilliant burst of light.

The strangest part of the regeneration was that Clara recognized the face in front of her.

The Doctor's old, owl-like face had been replaced with a young one with a big chin and coifed brown hair.