A/N: Thank you for reading this story. I am so, so sorry for the ridiculously long wait for this chapter; I didn't realise how long it had been since October. I hope it is worth it.

A quick recap: the TARDIS took Sherlock back to to see Arthur Conan Doyle, whom he is trying to convince that aliens are real and that he should help him. Meanwhile, John and Harry are on a kamikaze mission to try and rescue their father the Doctor from the evil clutches of the Daleks. Enjoy!

On board the Dalek ship, John was scrolling through a long list of various readouts from around the ship on a screen by the door, scanning each entry with his lightning-fast Time Lord's eyes. Across the room, Harry was squinting at a schematic of the ship which she had pulled up on another screen, zooming in and out of different sections.

After a while, Harry gave a shout and jabbed a finger at her screen. "Aha!"

John turned his head slightly, still scanning the list. "What have you found?"

She pressed a couple of buttons, and the ship's schematic appeared in front of her, a three-dimensional green hologram. "Come and look at this a sec."

He sighed and abandoned his multitudinous readouts, crossing the room in two strides. Harry turned to him and pinched the sides of the hologram with her fingers, enlarging it to get to the section she wanted. "There," she said, pointing.

John looked at it, then up at his sister. He looked back at where she was pointing to. "I see nothing of importance," he said slowly.

"Look," she insisted, still indicating the hologram with a finger.

"You're pointing at a doorway," he told her. "When was the last time you slept?"

Harry rolled her eyes. "I'm fine," she said. "Look at this door. There's a room behind it, but the room isn't connected to the door."

John frowned, and took another look at where the door met the room behind. Sure enough, the room in question ended in a wall on the side of the door, which seemed to lead to…well, to nowhere. The room, which seemed to be a storage space for spare armour parts, had a door on the other side which was connected to the room.

A smile slowly grew on his face, and he looked up at Harry. "Bingo," he said quietly. "Well done, Harry. I think you've found Dad."

Harry grinned at him, then glanced around at where the TARDIS had stood before it disappeared. Her smile faded. "I know we're going to go in there unarmed, and be all noble and everything…but I would feel a lot more confident with a gun over my shoulder," she confessed.

John stepped through the hologram towards his sister and placed a hand on her shoulder. "Are you sure you can do this?" he asked. "There's no Daleks on the ship, or not where they can get to you here. If you want, you could stay here…"

Harry swallowed and shook her head. She snorted at him. "You're not getting rid of me that easily, Johnny," she told him. "We're doing this together."

John's shoulders relaxed, and he stepped back. "Good," he said. "I mean, I would have done it, but I'm glad you-"

Harry rolled her eyes. "Shut up," she told him good-naturedly. "You need me, we both know that."

He nodded. "Don't I know it," he muttered.

She pressed some buttons, and the hologram disappeared. "Come on," she said. "Let's go kick some Dalek-"

-o0o-

"As fantastical as your claims are, Mr Holmes," Doyle conceded, "I must confess that there seems to be some sense in them. Perhaps you and your friends were being truthful after all."

Sherlock raised his eyebrows. "Well," he commented, "that was easier than I thought it would be."

"I am still not entirely convinced," Doyle added. "You have not yet shown me any proof, other than words and logic."

"What sort of proof do you want?" Sherlock asked, glancing at his watch. He had one minute left to convince Doyle that he was telling the truth. "I do not have anything from the 21st century…" He trailed off and looked at his watch, before quickly slipping it off and handing it to Doyle. "How about this?" he asked. "A digital wristwatch, purchased more than a century in the future."

Doyle took the watch and looked it over, his eyes slowly widening. "What is this magic?" he breathed, looking incredulously at the digital numbers. He inadvertently pressed a button, and jumped when the whole display lit up.

"It's the time," Sherlock explained, "shown in the military form. I presume you are familiar with twenty-four hour time?"

Doyle nodded numbly. He could do nothing but stare at the object in front of him. "But how is this possible?" he asked Sherlock.

"Technology will progress a long way in a very short space of time," Sherlock told him. "I'm afraid that a lot of it will be after your time, though."

Doyle eventually tore himself away from Sherlock's watch and handed it back to him, apparently satisfied that it was real. He steepled his hands under his chin again, in the position that was so familiar to Sherlock. "You said that you needed help?"

Sherlock smiled in relief, slipping the watch back onto his wrist and leaning forwards. "It's my friends who need help," he explained. "They are trying to find their father, but I am concerned that they may be entering a trap."

Doyle frowned. "However would I be able to help you?" he asked. "I know virtually nothing of your friends, or of their father."

"The letter," Sherlock explained, "that you received from Doctor Dalek. My friends believe that it was a coded note from their enemies, the Daleks. But I believe that it was a message from their father."

"You believe that this Doctor has sent them to find him?" Doyle inquired. "Why would he not just find them instead?"

Sherlock bit his lip. "I'm still working on that part," he admitted. "I suspect that time travel may play some part in the proceedings, but exactly how, I don't know. And I really don't like not knowing."

Doyle stood up with conviction. "Well, Mr Holmes. I must confess that I never thought I would say this, but I believe that you are telling the truth. I believe that you are from a different time, a different place, and that I was supposed to write a book about you."

Sherlock gave a genuine smile for the first time since he had entered the house. "I am glad to hear that," he told the author. "Does that mean you will help my friends?"

Doyle pursed his lips. "Your friends have not proven themselves to be entirely trustworthy," he said. "You, however, have. I will therefore assist you in finding the absent Doctor; but please know that it is not for them, Mr Holmes, but for you."

Sherlock glanced downwards and swallowed. He was not used to anyone declaring loyalty to him (other than John, of course, but he had recently revealed that he had another motivation for his actions). "All right," he said eventually, looking up at Doyle. "If you'll let me, I can take you to the TARDIS. It's a doorway," he explained before Doyle could ask for clarification, "to another dimension. The doorway can move through time and space, thus allowing someone within the dimension to go wherever and whenever they choose."

"Astounding," Doyle said. "And this doorway, it is currently in London?"

"That's how I got here," Sherlock confirmed. "It's hidden in an alley, several streets away from here. I could take you to see it, if you would like."

"At this hour?" Doyle seemed nervous for the first time. "Are you sure we will be safe, sir?"

He resisted the urge to roll his eyes. "I promise you, we will be perfectly safe."

Doyle closed his eyes and took a breath. Then he opened them and nodded resolutely. "This is madness," he said, "but I will go with you, Mr Holmes."

About time, Sherlock thought but did not say. "We can leave whenever you're ready."

Doyle stood up with zeal. "Let us go now!" he exclaimed, striding towards the door.

Sherlock coughed. "Mr Doyle?"

He turned around irritatedly, one hand on the door handle. "What is it?"

Sherlock nodded towards Doyle's attire. "Would it not be…prudent to perhaps get dressed first?"

Doyle glanced down at his dressing gown. "Oh," he said. "Perhaps you are right." He exited the room quickly, and Sherlock heard hurried footsteps going up the stairs. He rolled his eyes, and headed towards the door himself, to wait for Doyle in the hallway.

-o0o-

"Hold up a minute," Harry said, holding up a hand and stopping.

John halted next to her. "What is it?"

"I'm sure we've been through here before," she frowned. "I remember the scorch marks on this door." She indicated the door on her left, where there were indeed faded scorch marks, unrepaired from some long-ago battle.

John sighed. "I had feared as much," he admitted, beginning to walk again. "Do you have any idea where the hell we're supposed to go from here?"

"If I knew," Harry said irritably, turning a corner, "we would be there by now. Besides, you're the one who's supposed to be in charge."

"You're the one who was looking at the map!"

"All right, all right," Harry said. "So we're lost. We're looking for a door that doesn't fit with the rest of the ship. Shouldn't be too hard to find, right?"

"Right," John said resignedly. "Let's go."

They continued walking, this time with more determination. Harry took the left side, and John took the right as they walked down various corridors and around countless corners together.

"They all look the same," Harry said eventually. "The doors are all exactly identical."

John nodded in agreement. "All round, gold, shiny, polished, perfect…where are you going?" He stopped and turned around, watching his sister turn tail and run back the way they had come. He sprinted towards her, and caught up easily. "Where are you going?" he repeated.

"The door," Harry said breathlessly. "The one we passed three times. I noticed it because it was different, it had that scorch mark."

"So there was a fight," John said. "So what? And can we slow down?"

She slowed to a jog. "The whole bottom of the door was scorched," she explained quickly, "but nothing around it was. The floor, the walls around it, were fine. And none of the other doors were like that."

"Of course," John breathed, remembering. It seemed so stupidly simple. "How could we have not seen it before?"

"No idea," Harry said. "Maybe there was a perception filter, or maybe we're just thick." She quickened her pace again, and John followed, so they were both sprinting towards the door that did not fit with the rest of the ship.

They found the door in a matter of minutes, and both Time Lords came to an abrupt stop, taking a moment to catch their breath.

The siblings locked eyes for a moment, and smiled sadly at each other. Neither knew what they would find on the other side of the door, but both were almost certain they would not survive whatever lay in store for them.

John glanced downwards and clicked off the safety on his gun. "You ready?" he asked Harry, one hand hovering over the door handle.

Harry raised her gun, aiming it at the door, and nodded once. "Let's go."

John took a deep breath and pushed the button beside the door, running through as the door opened before him. Harry followed him, gun at the ready. The door rolled shut behind them, closing with a firm click.

-o0o-

It took longer than Sherlock expected for Doyle to get dressed, especially considering how eager he had been to leave before. But soon enough he appeared on the stairs, hurrying down and jumping from the third-to-last step to the floor. He crossed to the coat hooks behind the front door, picking up the thick cape which Sherlock had returned to him earlier, along with a warm overcoat.

After a moment's pause, Doyle held the cape out to Sherlock. He raised his eyebrows at Doyle, who kept his hand outstretched, indicating that Sherlock should take the cape.

He slowly reached out and took the cape. Doyle averted his eyes and pulled on the overcoat, clearing his throat. "Well," he said gruffly. "We should go." He pulled open the front door and stepped out, turning right and hurrying off.

Sherlock stepped out also. "Wrong way," he called, setting off to the left.

A few moments later, Sherlock heard footsteps hurrying up behind him, and Doyle appeared at his side. "I was testing you," he muttered, stuffing his hands deep in the pockets of his overcoat.

A smile tugged at the corner of Sherlock's mouth. "I'm sure you were."

They arrived back in the alleyway where Sherlock had left the TARDIS, to find that there was nothing there. Sherlock blinked, and turned his head around and back again. He squinted, but the TARDIS remained conspicuous in its absence.

He cursed mentally, and turned around to look at Doyle. The author was watching Sherlock with folded arms, tapping one foot, with an unimpressed look on his face. "Well, Mr Holmes," he said curtly. "This is a very interesting door, I must say."

"It was here before," Sherlock tried to explain.

"And now it isn't." Doyle turned to leave.

"Wait." Sherlock held up a hand. "Please. Just…two minutes."

Doyle stopped in his tracks. He sighed. "Very well," he said, turning back around and standing by the entrance to the alley, pulling his coat around himself more tightly.

Sherlock frowned, closing his eyes and pressing his fingers to his temples. The TARDIS had definitely been there before, right in front of where he now stood. Now, however, there was plainly nothing there, despite him having told the TARDIS not to move.

He opened his eyes and moved closer to where the TARDIS had been before he had left. His eyes darted around the alleyway, looking for a clue, any clue, as to where the time machine might have gone.

Absent-mindedly, Sherlock noticed that the cat from earlier was nosing around the alley, sniffing at something on the ground. It wasn't until the cat turned on a right angle that he realised that something was wrong.

Sherlock cautiously walked towards the cat, one hand outstretched at chest height. Tentatively, he moved forwards, until the tips of his fingers met a solid surface.

Sherlock flattened his hand against the cool, hard surface, marvelling at the fact that it was completely invisible. There were no distortions, no warped image on the other side, nothing to indicate that the TARDIS was in fact standing in front of him.

Sherlock began to move his hand, feeling his way over the invisible panels until he found the door handle. He curled his fingers around and handle and pulled firmly, watching as a gap seemingly appeared in the air before him, warm light spilling out into the dark alleyway. He heard a gasp from behind him, and a smile once again tugged at his mouth.

Doyle came up behind Sherlock, peering through the doorway in wonder. "After you," Sherlock said, giving a small bow and ushering Doyle inside the TARDIS.

Doyle stepped through into the bright interior of the TARDIS, mouth agape. He stared all around him, from the metal grate on the floor to the very top of the time rotor. He turned and went out again, looking around at the dark alley; then went back inside, jumping slightly at the jolting sensation as he crossed the threshold. "What was that queer sensation?" he asked Sherlock.

Sherlock followed him into the TARDIS and closed the door behind them, plunging the alley outside into darkness once again. "I believe that's caused by crossing dimensions," Sherlock said, striding to the console. "Thank you," he said to the TARDIS, before turning back to Doyle, who was staring at the console in wonder. "Do you believe me now?"

He tore his gaze away from the console to stare at Sherlock. "This is like nothing I have ever seen or imagined," he breathed. "If I am not dreaming, then of course, I believe you, Sherlock Holmes."

Sherlock smiled his smile which had become something of a trademark. "Excellent," he said.

"However," Doyle added, "I do not know what I could possibly do to help your friends. This…this technology is like nothing I have ever seen." He wandered over to the console and gently placed his hands on the edge, feeling the distant thrumming of the engines. He looked up at Sherlock beside him. "I must confess myself to be lost, Mr Holmes. This environment, while amazing, is completely unfamiliar, and your circumstances are like nothing I could have imagined. I never even thought time travel to be possible, and now you want me to help you to save two friends who are not even of this planet. I would love to help, Mr Holmes, honestly I would. But I fear I would have no idea of what to do."

Sherlock shook his head. "I have no idea, either," he admitted. "I am every bit as lost as you. All I know is that John and Harry are heading into a dangerous situation without thinking it through. My brain is great, or so I am often told. But as it was you who created me, so to speak, your mind must surely be every bit as good as mine, if not better."

Doyle noticed that Sherlock did not seem particularly pleased about this idea. "Very well," he said. "I will attempt to help you, but I cannot promise that we will get a result."

Sherlock's shoulders relaxed slightly. "Thank you," he said.

Doyle held up a finger. "On the condition," he said, "that you bring me back here when we are done. And to this year, if you please."

"You are standing," Sherlock told him, "in the best time machine in the universe. I could bring you back to five minutes after now, or five minutes before we arrived here. You will get back."

"Unless we are both killed by these Daleks," Doyle pointed out.

Sherlock frowned. "I wasn't going to say that."

"But you thought it."

"You know me too well."

"Of course I do," Doyle said, rather too smugly in Sherlock's opinion. "I created you."

Sherlock ignored him, walking around the console to where he had stood when talking to the TARDIS before. He cleared his throat awkwardly. "Um. Hello," he said, directing his words up to the time rotor. "Again. You let me in this time. Does that mean I was supposed to bring Mr Doyle here? I presume you're invisible for his benefit?"

There was no response from the large console. Sherlock tried again. "But what now? You have us here, Sherlock Holmes and Arthur Conan Doyle. Surely that would cause a paradox in some universe."

A light on the console suddenly flashed bright green. Doyle jumped, but Sherlock barely glanced down before looking up again, a small smile forming on his lips. "I said something right," he mused.

"Paradox, perhaps?" Doyle suggested. Sherlock's looked towards him, and indeed the whole attention of the room seemed to shift towards the would-be author. "I mean," he continued, "that time travel must be complicated, however it works. Contradictions must surely arise on occasion. Might these be the paradoxes to which the TARDIS is referring?"

Out of the corner of his eye, Doyle saw the light on the console flash red. "Oh," he said. "Apparently not."

"Was it when I said universe?" Sherlock asked, and the attention of the room shifted back to him. "Are there multiple universes involved here?"

"Are there multiple universes at all?" Doyle inquired.

"I have no idea," Sherlock confessed. "It was a flippant remark, that's all. I didn't think it would mean anything."

On the console, the green light flashed twice. "Apparently your flippant remark is significant," Doyle observed.

"Different universes," Sherlock mused. "Are you familiar with the multiverse theory?"

"I cannot say I am, no. Would you care to explain?"

"I can do better than that," Sherlock told him. "I can show you."