Danni didn't do much for the longest time. She just stared at the message like she couldn't quite comprehend the words. It was only a single sentence, and the words weren't particularly difficult, but for some reason her brain couldn't quite process what he was saying.

Steal your husband's TARDIS and come save me.

The fact that he was even asking proved that he was in bigger trouble than perhaps she had first read into, but also the fact that he wanted her to steal the TARDIS and not tell the Doctor told her it wasn't the worst thing that could have happened to him. Missy may have been more inclined to listen to the Doctor, but he definitely was not.

She wasn't sure if she appreciated how a single line in an email had her thinking over a man who hadn't exactly treated her well like he was an old friend. However, as she looked up at the selfie he'd sent her, she still couldn't help but smile at the sight.

When she had been trapped with Missy she'd had to learn how to survive. Checking for doors in the walls was one way that she had done so, as Missy would trap her in virtual worlds often with only a single door as a failsafe to escape. It was one that she didn't use very often anymore, but sometimes she found herself checking for them. Another was in her dreams. Missy somehow always knew when she was dreaming about the Doctor, but she never really minded if she was dreaming about her previous body. Danni had always assumed that as long as she was dreaming about any Master then Missy thought she was winning. So Danni had created a man in her head, with his face and his mannerisms, who had become a comfort to her. A friend.

The sight of the selfie proved just how bad of a coping mechanism that had been, because she was really glad that he was still alive somewhere, but also knew that it was a terrible thing for him to be loose in the universe. Especially if he was seeking her out directly.

No, I won't do that.

She typed the reply but didn't immediately click send, which again was a terrible sign. She deleted the simple sentence and tried again.

No, I'm not stealing a TARDIS and bringing them you. That's a terrible idea.

She didn't know why she couldn't send the replies. They were what she wanted to say to him, after all. She wasn't about to take the TARDIS and fly it to him. Last time he'd managed to get his hands on a TARDIS he'd created a paradox machine. She might have been stupid, but she wasn't that stupid.

She's my TARDIS too. I can't steal what is mine.

She closed her eyes after she clicked send. It was the truest thing she could bring herself to reply to him. After all, whilst the TARDIS was technically the Doctor's, they had been married long enough that she could also claim the blue box as her own. Enough, anyway, for a Time Lord who was stuck god only knew where.

Fine, be delusional. Come get me.

She was very proud of herself for what she did next. She typed out a single word reply, hit send, then immediately slammed the laptop shut. She put it on the floor and climbed under the covers, where she was very comfortable as she forced herself to put it out of her mind.

In hindsight, she should have known that her resolve was going to be rather weak, but at that particular moment she had won the battle and she took that into her dreams.

No.

~0~0~0~

The Doctor, so far, had done very well keeping the fact that he couldn't see to himself. He'd enlisted Nardole as his helper – who had protested, but only minimally – and his sonic sunglasses had proven to be quite the useful tool. As he looked out across the lecture hall, he couldn't actually see anything at all, but the glasses projected the readings into his mind. The hall was full, as it was normally, which was always a bonus because even though he could speak to an empty room he didn't particularly want to. He quickly looked for both Bill and Danni, who were sat on opposite sides of the room. Danni was surrounded by the gaggle of students she had picked up.

How no one had figured out his ruse was baffling, he thought to himself as he walked into the corner of the lectern. Perhaps he was just clumsier that he thought he was.

He still had absolutely no idea if he could ever fix his eyesight. It wasn't like there were hospitals that specialised in healing Time Lords, and he wasn't sure if using regeneration energy was the best course of action. Part of him didn't want to use it because Danni didn't know and he didn't want to use up regeneration energy unless he absolutely had to. The other was scared to try in case it didn't work.

His sonic sunglasses were incredibly clever – of course they were, he'd made them – and when he'd finished his lecture, he looked over at her. They highlighted any and all information he may need to know about any person around him, but for his wife they just let him know she was there. He knew she'd notice if he didn't look to her after the lecture, and by the way she seemed to be moving he'd managed to convince her yet again.

Ultimately, he didn't know what to do. Nardole had been pressuring him to tell his wife, but he always agreed when the Doctor argued against it. He didn't like lying to her, but he had to keep her safe. He had to keep everyone safe.

Sometimes being him was so tiring.

She waited until all of the students had gone, including her friends, before approaching him. "Interesting lecture," she told him. "I thought you were going to actually talk about physics today?"

He frowned. "I did, didn't i?" he asked.

"No, sweetie. The everchanging perspective of one's self isn't physics related."

"Ah," he replied, remembering how he had managed to fall onto that tangent. "I'll have to try harder next time."

"Don't, it was really interesting," she replied. "Kyle's invited me 'round to their house. Apparently they've got some sort of Mario Kart tournament going on. He wants me on his team cause they're a man down."

"More fool him," the Doctor muttered and she shot him a look that he didn't see. "So I shan't be seeing you this evening, either?"

"Sorry, I know I've been a bit busy. Tomorrow night I'm all yours, I promise." He also didn't see her glance behind her to make sure the coast was clear before kissing his cheek. "Give me a call if you need me."

He caught her hand. "Always," he purred and she squeezed his hand before letting it go.

"Love you."

She said it as she walked out, which was yet another step in proving just how comfortable she was becoming. Even though Kyle and his little group of friends were taking more of her time, he was sure that having some friends outside of him and Nardole was really helping her feel better equipped to handle life.

He stood at the lecture until the lights turned off, just pondering his next move in his life, when the door opened. He glanced up and his glasses immediately registers many, many people entering, lining up at the top of the lecture hall.

"Hello?" he asked, rather concerned. "Hello? Who's there?"

All of the people stopped, except one, who walked down the stairs towards him. "Good evening, Doctor. We have come here today direct from the Vatican."

He didn't expect that. "Oh, right, that's nice," he replied. "Well, if you've got a collecting tin, I'm sure I can find something." He reached into his pocket as the door to the side of the lecture hall opened. "Er, leaky roof, is it?"

Nardole had just been coming to fetch the Doctor, but when he saw all the people and how they were dressed, he knew he had to intervene before the Doctor accidently insulted someone. "Oh, no. No, no, no, no, no. Stop talking. Stop now," he said as he rushed down the stairs to the Doctor's side. "Please, just listen to them. It sounds important."

The Cardinal stepped closer. "We have come here to see you because your services and wisdom are recommended at the highest level." He held out an old scroll and Nardole, knowing the Doctor wouldn't be able to see it, moved forward and took it. He held it open as if he was showing the Doctor. "As you can see, this is the personal recommendation of Pope Benedict IX. In 1045."

The Doctor smiled fondly, falling back into a memory for a moment. "Pope Benedict. Lovely girl. What a night. I knew she was trouble, but she wove a spell with her castanets."

"Doctor!" the Cardinal interrupted, becoming a little exasperated. "On behalf of every human soul in this world, of any creed, of any faith, with the utmost respect and in complete secrecy, His Holiness, the Pope, the Bishop of Rome, requests most urgently, a personal audience."

"Well, if he's so keen to talk to me, why doesn't he just come here himself?" the Doctor asked as a man all in white started walking down the stairs to the lecture platform.

"He is here. He's standing right in front of us," Nardole muttered under his breath.

The Doctor shifted slightly, feeling like he was about to blow his secret and needing to get focus off his mistake. "Hello, uh, the Pope," he greeted awkwardly. "I'm sorry that I didn't recognise you there."

He paused, and then he frowned. "You don't do this," he declared. "The Pope doesn't zoom round the world in the Popemobile, surprising people." He leant forward, very intrigued and slightly concerned. "Why would you do that?"

After the Cardinal and the Pope shared a few words, the Pope replied with only one thing. "Extremis."

The Doctor waited for a moment, hoping for some more information other than a rather pompous way of saying the Pope was desperate which was why he was suddenly paying house calls. No one said anything, though, as the room fell into a solemn silence and it was Nardole who broke it, clearing his throat.

"Sir, perhaps we should move to your office?" he offered as a prompt. "Where we can discuss things more privately?"

The Doctor pointed in what he assumed was the right direction. "Yes, that is- that is a good idea," he agreed. "We just need to make a bit of a pitstop, then we can get down to- get down to business."

Nardole frowned but followed the Doctor as he made his way down from the platform. "Sir, where else could we possibly need to be?" he hissed.

"The Pope is here. He doesn't just drop by for tea and crumpets, does he? Something very big, and very interesting is happening. We are going to go crash a game of Mario Kart."

~0~0~0~

Danni, apparently, was rather good at Mario Kart. Or so Kyle had told her as they seemed to be winning pretty much every game that they played. After learning how to pilot the TARDIS, though, using such a small controller with limited controls didn't exactly seem too difficult. She was sure that with a little less music, and a little less booze, that they'd have been winning every match they played.

She was rather fond of the red shells, but she hated the blue ones. Those had bitten her in the arse more than she'd care to admit.

The doorbell rang whilst they were waiting for their next turn as teammates. There were quite a lot of people at the house party, but their little group seemed to have taken over a corner of the room and Danni was very happy not to interact with everyone else. She really enjoyed hanging around with the other students, but she only had the tolerance for so many people.

"It seems very unfair that she's on your team," Boyle pointed out. "She's super smart, of course she was going to be good at gaming as well."

"It's not my fault that you all paired off without me," Kyle protested. "Plus, she could have been absolutely awful."

"That's true," Danni interjected before taking a sip of her drink. "I mean, it's highly improbable I'm terrible at anything, but I haven't tried everything yet, so there might be something out there." She frowned, thoughtful for a moment. "Am I doing it wrong?"

"Doing what wrong?" Sarah asked.

"Being a person," she replied. Everyone laughed, but it had been a serious question and she wondered if that was how the Doctor felt when he thought he'd done something right but everyone looked at him like he had two heads.

Kyle wrapped his arm around her shoulder and she stiffened slightly at the surprise contact. "Nah, you're good," he promised.

"How's your husband?" Sarah spoke up in a pointed voice that Danni didn't quite understand, but also made Kyle remove his arm so she wasn't going to question it. She still wasn't quite comfortable with touches that came from nowhere, no matter how innocent they were.

"Fine. Working," she replied shortly in the hopes that it would force them to change the conversation.

"When are you going to bring him?" Kyle asked. "I'm starting to think he doesn't exist."

"He does. This just isn't his type of thing."

"You don't think he's going to like us," Kyle teased.

"Well, no, he probably won't. But he doesn't like most people, so that's not anything to do with you lot," she reasoned. "He's just- I don't know, not the going out to get pissed kind of guy."

Plus, there was the whole 'he's a teacher and we're undercover aliens' thing that she was desperately trying to keep under wraps, but the Doctor really wasn't going to appreciate a bunch of students playing Mario Kart.

The music was turned down slightly and Danni was rather grateful that the conversation was ended before she had to start pulling excuses out of her arse. "Hey, is there a Danni here?" someone shouted.

Immediately the group of ten or so people, minus Danni, all raised their hands above the heads to indicate that she was there. She wasn't particularly happy that they'd pointed her out considering how she would rather not have been highlighted, so instead she just craned her neck to try and see who would visit her at a party.

Was it Bill? She was also a student, after all, and would be hanging around with people of similar age. Was she about to have another awkward encounter with her husband's student?

Apparently, not, as the short, dumpy, figure of Nardole rushed over. "Nardole!" everyone else cheered happily, as they all apparently had taken to Nardole rather well. Danni wasn't as enthusiastic at seeing him.

Nardole offered them all a little, awkward wave. "Hello."

"I didn't know you were coming," Kyle said. "You should have said, I woulda found someone else to be on your team."

"We can always share him," Boyle offered. "Give Miss Perfect Score here a rest."

"Ah, no, no, I'm not here to race," Nardole interrupted and the whole group groaned. "Danielle, I just-I need to speak to you."

She pushed herself off her chair and followed him outside. Immediately her cool exterior fell. "What are you doing here?" she hissed. "What's wrong? Is it Missy?"

"No, she's fine, she's still in the vault," he reassured her and she felt an immediate sense of relief. It was never good when Nardole appeared unannounced like he had done.

"Is it the Doctor, then?"

"Sort of. He's asked me to come get you." He nodded towards the other end of the street, where the TARDIS was parked. "Something's happened he thought you might… How drunk are you, exactly?"

"Not very. A little. I guess. Why?"

He grimaced. "Can you sober up any?" he asked. "Very quickly?"

She stared at him, eyes narrowing. "What's going on, Nardole?"

"Um, well…"

~0~0~0~

"The Pope!" Danni hissed under her breath. "Why the hell wouldn't you mention that it was the bloody Pope?!"

"The Doctor said you wouldn't come if I told you," Nardole replied quietly, shooting the Cardinal a queasy grin.

"Then you should have told me," she retorted. "I'm drunk, I shouldn't be here!"

Nardole had taken her to the Doctor's office, where the Doctor was ready and waiting at his desk, with the Pope sat on one side and a lot of men in religious clothing waiting outside the door. The Doctor had greeted her happily and she had slightly stumbled out of the doorway. It wasn't as if she had drunk absolutely loads of alchol, but for some reason even one drink now felt like twenty.

"I did ask," he reminded her.

"No, you didn't."

He most definitely did, but he just huffed to himself. She was just tipsy enough that she would start arguing in front of the Pope, and that definitely wouldn't go down well.

She wasn't even sure f she was supposed to be there. The Catholic Church wasn't exactly renown for its treatment of women, but she was still stood next to Nardole, who in turn was stood next to the Doctor.

"There is an ancient text buried deep in the most secret of the Vatican libraries," the Cardinal explained. "A text older than the Church itself. The language of this text is lost to us, but thanks to the work of an early Christian sect, the title has survived."

He pulled out a torn piece of parchment, with most of the wording missing, but the title was very prominently written at the top. He slid it over to the Doctor. "Okay, so what's the title?" the Doctor asked.

Danni looked down at him, confused and she opened her mouth to comment on the fact that he was being rather rude. Nardole, seeing that she was about to question the Doctor about something he couldn't see, leant forward and interrupted her before she could. "Oh, yes, I can see that it says Veritas." He brought it over and put it in front of the Doctor, so that it seemed like he was going to read it.

"Literally 'the Truth'," the Cardinal translated for them.

"Obviously, this sect, they understood the language," the Doctor prompted.

"It died with them. And all copies of their translation disappeared shortly after their mass suicide," he explained. "A few months ago, after many centuries of work, the Veritas was translated again."

"Right? And?" Nardole prompted.

"What did it say?" Danni asked.

"No-one knows," the Cardinal replied. "Everyone who worked on the translation, and everyone who subsequently read it is now dead." The Pope looked rather unsettled, like he didn't even like hearing about it. "Dead, Doctor, by their own hand."

"Mass suicides?" Danni asked, surprised at the dark turn that the conversation had taken. "All of them?"

"In every case. Beyond doubt."

"All bodies recovered?" the Doctor asked.

"Except one, but we naturally assumed that he had…"

"Assume nothing," the Doctor cut in. "Assumption makes an 'ass' out of you, and 'umption'. Cardinal, one of your translators is missing."

The Cardinal leant forward. "Doctor, those translators were devout. Believers. They took their own lives in the knowledge that suicide is a mortal sin. They read the Veritas and chose Hell."

"Dottore, will you read the Veritas?" the Pope begged.

"Absolutely not," Danni replied for him. "That's a stupid request."

"Danielle," Nardole hissed and she shot him a rather annoyed look.

"Oh, don't 'Danielle' me," she retorted. "Look; I may be a little tipsy, that's to be expected when you pull me from a party, but don't tell me I'm not saying anything irrational." She took the scrap of paper from the Doctor and slid it back. "You shouldn't be trying to translate this; you should be burning it."

The Doctor turned in his chair to face her. "Knowledge is power, remember?"

"Not that kind of power," she replied. "Everyone who had ever read this has died or gone missing. What makes you think you'll be any different?"

"Because," he started before reaching out and, thankfully, grabbing her hands. "Because this is something new, something no one else knows about. Something that no one else in the human race can read. Because I'm not human."

"You think that being an alien on this planet is going to save you? That's a small margin to bank on."

He nodded to the Cardinal and the Pope. "That's why they're here, my Pet. Because humanity has failed, so they've had to go further beyond."

She pressed her lips together and, even though the Doctor couldn't see, he knew what that silence meant. "You are not invisible just because you're not human," she stated.

"And we have both seen worse things than a killer piece of writing," he replied. He gave her hands a squeeze. "And I know you're just as interested as me."

"No, I'm not."

"Yes, you are." He smiled. "You would have chucked the Pope and his friend out of here by now if you weren't."

She, again, didn't reply straight away and that was because she knew he was absolutely right. She blamed it on the booze she had been drinking prior to being brought home. But there is a killer piece of writing that was taking out religious men and she had to know what that was about.

She sighed heavily. Why did it always have to be him? "Fine," she muttered. "But this is the last time."

~0~0~0~

Bill stormed into the TARDIS, fury on her face as she ignored all of the other people who normally wouldn't be there. She looked up at the upper walkway, where the Doctor was walking around, being followed by a Cardinal. She knew she should have questioned it, she knew she should have said something about all the religious men, but she much too angry to be able to form more than one thought.

"Doctor! Here's a tip. When I'm on a date, when that rare and special thing happens in my real life, do not, do not under any circumstances, put the Pope in my bedroom!" she ranted loudly.

Nardole looked at Danni, who has a small smirk on her face. "You said she wasn't on a date," he pointed out.

Her smirk didn't drop. She'd seen how nicely both Bill and the woman she was with had been dressed, and how close they had been stood together when they had scanned Bill's flat to make sure she was actually there. She also knew that the Doctor and Nardole would have had absolutely no clue what that meant. The Doctor had been adamant that they brought Bill along, so leaving her to the date hadn't been an option. So, she'd seen the opportunity and took it. "I know what I said," she replied.

"Oh, you're being cheeky again."

She shrugged. "It happens."

"Okay. Now I know. Air cleared," the Doctor replied offhandedly to his student. He sat down at one of the desks, a small device in hand that Danielle could not know he'd found. "Nardole will explain what's going on."

Nardole, once again being given all of the jobs the Doctor didn't like, moved over to Bill. "Well, you know the Vatican?" he asked as the Cardinal approached the Doctor. "The one in Rome? In Italy?"

"I'm sure she knows where the Vatican is," Danni interrupted, slowly walking over to the pair. "She's not an idiot, Nardole." She looked at Bill, now looking slightly bored. "There's the text in the Vatican library that has caused every person who's read it to kill themselves. They want the Doctor to read it to find out what it says."

Bill looked alarmed, which Danni appreciated. "And he's actually going to do it?"

"You think he would turn that away?" she retorted. "He can't help himself."

"And you're okay with that?"

"If he wants to get himself killed, that's on his head," Danni replied. "He's always done stupid things for stupid reasons. At least he's got a better chance of surviving this than taking off his helmet in a vacuum."

As she walked away to the Doctor, Bill turned to Nardole. "What was that about?" she asked him. "I know I stuck my foot in it a few times, but that was uncalled for."

"Ah, she's a bit drunk, I wouldn't pay too much attention," he tried to dismiss.

"Nah, that's not it." She looked up at the pair. "I just don't get it. They seem so different. Is she in it for the money, or sommat?"

Nardole never really liked to get in the middle of disagreements, it had gotten him into a lot of trouble in the past and ultimately led to him losing his head in the first place. "She's just not very comfortable around people. I wouldn't take it too personally."

~0~0~0~

Danni looked down at the small, black box that the Doctor was holding. "What is that?" she asked. "I've never seen it before."

"It's a reading device," he explained, just as he had done for the Cardinal.

"Oh, will it read for you?" she asked. "So you don't have to actually read it yourself?"

"Something like that," he lied vaguely. He hated not being able to see her. A sign on a screen in his brain was definitely not enough. He reached out and took hold of her hand. "Danielle, when we get to the text…"

"You don't want me to read it unless I absolutely have to," she cut in. He frowned, looking up at her and she rolled her eyes. "Honestly, sometimes I think you think I'm stupid. If something goes wrong then both of us can't die. There's too much at stake and I, for better or worse, have that little bit of human in me that makes me infinitely more susceptible to whatever the writing says. One of us needs to stop the killer writing, and one of us has to stay alive to keep Missy under guard."

Of course, she was absolutely right on all accounts. Just because he thought Missy was doing better didn't mean that he thought she was ready to be free. And she was part human, which was the only thing they currently had linking the dead and missing people together, and also one of the only things that made the Doctor the perfect test subject.

"I thought you might have protested more to being left in charge of the Vault," he admitted.

It wasn't like she was thrilled about it, but there were emails sat in her inbox that told her that a Missy contained in one place was so much better that a Master roaming the universe. "Well, one of us has to be responsible in this relationship, and evidently that is never going to be you," she teased.

She laughed in surprise as he pulled her down into his lap. "I should hope neither of us would be too responsible," he told her before putting the device in his jacket pocket.

"Doctor, sweetie, the Pope is still here," she reminded him. He jolted slightly in surprise as he also remembered that fact. He did take comfort in the fact, though, that he probably would have forgotten even if he had been able to see the man in white.

He didn't let her go, though, and she didn't make any move to stand up. Him holding her without a care of the people around them was just another reason that she was happy she'd stood up to Koschei and hadn't gone running after him.

"Uh, Sir, we've landed," Nardole called up to the pair.

"Ah, well, until next time," the Doctor murmured in her ear. "Perhaps when we're finished, we can find that room Benedict pointed us to."

Danni slipped off his lap. "Oh, what a night that was," she said. "We should drop back in, let them know we escaped."

"I'm sure they've realised by now."

~0~0~0~

The Pope was very eager to leave them to head into the Library with the Cardinal Angelo, who took the small group through a hidden passage guarded by Pope Benedict, who looked just as sassy as Danni remembered.

The Haereticum was absolutely stunning. The walls stretched upwards and outwards, lined with books containing everything that the Church didn't want to be public knowledge. Danni had the incredibly strong urge to grab everything she could see. What a waste it was to keep all the knowledge locked away.

"Very few know this place exists," Angelo explained. "The library of blasphemy; the Haereticum."

"Harry Potter!" Bill immediately said with a giant grin on her face.

"Language," the Doctor scolded.

"Please, stay close to me. The layout is designed to confuse the uninitiated," the Cardinal explained.

"Sort of like religion, really."

They followed the Cardinal down the middle aisle before turning off to the left. Danni ran her finger across the shelves. Surprisingly, only a small layer of dust stuck to her fingertip. "I wonder which poor bastard has to clean all this."

"Language," Nardole scolded. "We're in the Vatican."

"And?" she retorted. "Surely that's the best place to swear. No one else does, it's good to have a varied vocabulary."

"It's not very respectful, though, is it?"

"Well, to be honest, they've not been very respectful to me, have they? Or have you forgotten how to Catholic church has treated the females of this planet in the past?" She looked up at the ceiling. "I'll stop swearing when they give me more rights. I wonder how many of the Pope's goons are female? I think it'd be a good bet to say none at all. Benedict would be furious."

"I think Benedict would be furious that we were back in the Vatican and not being locked up," the Doctor said. She couldn't disagree with that, and so went back to running her fingers over the spines of the books. The Doctor, instead, turned to Bill. "Who was your date, then?"

"Er, Penny," Bill replied wondering if this was the best place to be asking about her personal life. "Uh, it's a long story."

Danni stuttered in her step as Angelo pulled a lever on the side of one of the many book cases to turn on the lights. She had heard that phrase many times over her life. People often said it before launching into mundane and long stories that explained incredibly uninteresting things, which she hated just because it was a waste of her time.

She had another experience with it, though; one that chilled her down to her core and that put her on edge more than she had been in a long time. She'd heard it from multiple people, even herself, when her brain couldn't be bothered to fill in the blanks to a situation. She'd heard it time and time again when she'd been put into a dream state so Missy could play with her.

'It's a long story' meant only one thing to Danielle; that everything around her was fake.

Nardole, instead of following on with the Doctor and Bill, also came to a stop when he realised that she wasn't moving anymore. "Danielle?" he asked, concerned, which caused the Doctor to stop and turn around. "What's wrong?"

She looked at Nardole, eyes wide and he frowned even further. He wasn't real, was he? Had he ever been real? Was the Vatican real? Was Bill and the university real?

Was the Doctor real?

And, really, did she want anyone else to know that she'd worked it out? She needed time to think, to work out exactly when she'd appeared in the dream, and just how much of her life was a lie? Had she even escaped in the first place? Was that why the memory of Clara still tainted everything, even though she couldn't remember her friend at all? Because it was all fake? Because she hadn't lost them, but they were being supressed by someone else?

She swallowed hard. "I'm fine," she told them all in an attempt to stop everyone looking at her. "I- I thought I saw a rat."

The Doctor rolled his eyes behind his sunglasses, but reached into his pocket all the same and pulled out a small bottle of hand sanitiser. He should have known that her dislike of getting dirty would flare up in the Vatican, and he was glad he actually was prepared for once. He chucked it to where his glasses told her she was standing and she caught it.

Angelo led them further into the Haerticum, to the very centre where a cage was sat, illuminated by the circular lights that hung from the ceiling. Just as they were about to reach it, they were all stopped in their steps by a blue light that shot from one of the many aisles of books.

"Doctor!" Nardole exclaimed, which brought the Doctor to a stop as well.

"What is that?" Bill asked.

"I don't know," Angelo replied. Danni didn't say a word. She had a horrid, dark, unsettling feeling that was twisting everything around her. She had her suspicions over what, exactly, it could be and she really didn't want it to be true.

The Doctor, who couldn't see anything at all and nothing was showing up on his glasses, turned to Nardole in the hopes he would say something to tell him what was going on. "Oh, look, it's a mysterious light, shining round a corner, approximately ten feet away," he explained.

"Hello? Who's there?" Angelo demanded before heading into the light and down the aisle. "This library is forbidden!"

"No, wait!" Bill cried as she followed him. At the end of the aisle was a wall, and on the wall was a bright oval of light with a silhouette in the middle.

"Who are you? What are you doing here? Speak! Speak to me," he continued to demand as they all shielded their faces from the bright light.

The Doctor, who could now see the source of the light as well as the silhouette, tried to analyse who it might have been. However, the sonic sunglasses couldn't pick up any information about the person, which was more worrying than he would have liked to be.

"What's through there?" he asked the Cardinal. "What's through the door?"

"There is no door there," Angelo replied. "It's a wall."

The light flared up the disappeared, revealing the wall and not much else. Angelo rushed in front of the Doctor and to the wall, feeling across it. "Impossible. Quite impossible."

"Not really," Danni muttered.

Bill looked at her. "What do you mean?" she asked. "There was a hole in the wall, and now there isn't!"

"Doors are hidden in walls all of the time. If you're not able to see that, then it's very short sighted of you," she replied. Her hands were clenching by her sides as she tried to calm the urge to rush over and open the hidden door herself. Nothing good ever came from leaving Missy's little stories straight away. "Doctor?" she called to her husband. "The Veritas?"

He nodded. "Right, the Veritas," he agreed. "I have a feeling the answers might be there."

"I have to check if there is a breach in the wall. I'll unlock the cage in a moment."

The Doctor really didn't have time to wait for that, so he covertly unlocked the door himself. Bill and Nardole headed towards it, but he stopped next to his wife, who hadn't moved from the top of the aisle. "Danielle," he started lowly, placing a hand on her arm. "It's not what you think. This is all real, I promise."

She looked at his hand. She should have known that the Doctor would be able to work out exactly what she was worried about, and the thought should have calmed her down. Instead, all she could think about was how it would be very like Missy to plant a Doctor who was just caring enough that it would bring her guard down and take her suspicions away.

"I know," she lied. "It's all very interesting, isn't it?"

He gave her arm a squeeze, proud of how far she had come. "I fear it may become even more so soon enough."

"Oh, my God!" Bill exclaimed just as they reached the cage. A priest had appeared in the cage, looking incredibly worried, with a gun in his hand.

"I'm sorry. I'm sorry," he repeated, his voice breaking as he sounded like he was going to cry. "I sent it."

The Doctor frowned. "Sent what?"

"I sent it, yes," he replied.

"Sent what where?" he pressed. Instead, the priest ran out of the back of the cage and disappeared into the library. Bill made to run after him, but Nardole grabbed her arm before he could.

"No, stop. You'll just get lost."

"And he had a gun," Danni added. "That's not a fight you would win."

It sounded as if the words should be concern, but to Bill her tone sounded like she was saying it as an insult. The cage has a desk in it, with an ornate chair on one side. An old book declared itself to be the Veritas as it sat in the middle of the desk, as if it was on display, but Danni headed straight for the laptop that was sat next to it.

"Hey, there's Wi-Fi down here," Bill declared, sounding rather amused.

"Of course there's Wi-Fi," the Doctor replied as he felt his way to the chair. "It's a library."

Nardole quickly checked it over to make sure it was safe for him to sit in. "Reading chair with a safety belt?"

Danni glanced up from the screen to take a look. "Always promising, that," she muttered before turning back to the screen. "Four hours ago our runaway priest friend sent a copy of the translation to CERN."

"What's CERN?" Bill asked.

"The European Organization for Nuclear Research," the Doctor replied. "The largest particle physics laboratory on this planet. Did they reply?"

She nodded. "Just now, and just three words." She turned the laptop to face him. "Pray for us."

"When do a bunch of scientists ask for prayers?" Bill asked.

"The same time anyone does. When they're very, very afraid." The Doctor pulled the book towards him, feeling the letters carved into the front. This was definitely the right book, at least. "Particle physicists and priests. What could scare them both?"

Danni knew one thing that should scare everyone on the planet, but even she had her doubts that the contents of the book would contain anything about Missy. "Whatever in that book is really dangerous."

"He's been down here for a while, that guy. Whoever he is."

"At a guess, the missing translator," the Doctor replied as he pulled out his sonic screwdriver and pointed it at the book. Danni frowned; she hadn't seen it for a while, and had thought that he'd replaced it with the sunglasses.

Was that just another inaccuracy that Missy had put into her simulation? Was it purposeful, was she supposed to call it out? Was it a test?

"Oh, that's promising," Bill continued as if she had no idea about the battle that was going on in Danni's head.

"Promising?"

"Yeah, at least one person read the Veritas and lived."

As if on cue, as if someone was telling a story, there was a gunshot off in the direction that the priest had run to. Danni rolled her eyes. "You had to say it, didn't you?" she snapped before she turned to the Doctor. "I'm gonna go see if there's anything left of our friend. Don't do anything stupid."

"I wouldn't dream of it," he drawled as she walked out of the cage and in the direction of the sound. At that moment, with her reality crumbling around her, she was just glad to be getting as far away from him as possible. Nothing broke her hearts more than a fake Doctor.

"She seems particularly moody today," Bill commented as she watched the other woman walk away.

"Ah, that's because I interrupted her night out," the Doctor offered, even though he knew that wasn't the reason. He understood exactly what would be going through his wife's mind the moment they came across the door in the wall that shouldn't have been there. He knew where her mind head taken her to, because for a brief moment it had taken him there as well. However, he knew his grasp on reality was normally slightly better than hers and he had dismissed the idea that it was Missy behind everything, whereas she was most likely fixating on it. "A bit like you. Perhaps she was on a date."

Despite the gunshot, and the rather worrying situation where scientists were turning to religion for help, Bill's eyebrows shot up. "What, seriously?" she asked.

The Doctor was too engrossed in getting to read the book in front of him to see that she hadn't taken his comment as a joke. "Why don't you two go after her, make sure that they're both alright. He's about fifty feet that way." He pointed in the direction Danni had headed.

"Are you trying to get rid of us?" Bill accused.

"Why?"

"Because you're sending us into the dark, after a man with a gun," she pointed out.

"No, I'm sending you after my wife, who went into the dark after a man with a gun. Very different," he corrected. She wasn't wrong, though, so he pointed at Nardole. "Nardole, make sure you walk in front of Bill.

He didn't move and Bill knew exactly why. "Are you going to read this? Is that why you're sending us off?"

"I won't read this without you."

"Really, he won't," Nardole muttered before taking hold of Bill's arm again. "Come along, who knows what trouble she's getting herself into."

As they walked away with a promise from the Doctor that he wouldn't read the book without them, Bill turned to Nardole. "Was she really on a date? Did I stumble into, like, a moment between the two?"

Nardole sighed. "No, she wasn't on a date," he insisted. "This isn't a soap opera, Bill. They're just two ancient aliens who have spent thousands of years together travelling space and time. It's nothing strange."

"Yeah, not strange at all," she muttered before picking up her speed slightly. She would never understand the pair, she was sure of it. She'd seen Danni hanging around with a group of other students recently, was it really what the Doctor suggested? She didn't seem like the type of person to suddenly have friends.

Nardole walked in front of her. "You're to walk behind me now, like the Doctor said," he warned her.

"Yeah, totally not happening," she replied, shooting him a look. He turned to face her, removing his glasses and suddenly he looked more serious than she'd ever seen him.

"Okay, Bill. Miss Potts." He straightened slightly. "I am the only person you have ever met, or ever will meet, who is officially licensed to kick both Danielle's and the Doctor's arses. I will happily do the same to you, in the event that you do not align yourself with any instructions I have issued which I personally judge to be in the best interests of your safety and survival." He smiled, putting his glasses back on, ignoring the stunned look on her face. "Okay, Bill?"

She nodded. "Okay," she agreed.

"Good-o!" They continued on, Bill behind Nardole and suddenly looking at him in a new light.

"Nardole, are you secretly a badass?"

"Nothing secret about it, baby doll," he replied.

"I told you to stop calling people that. It's weird," Danni declared as she appeared out of one of the many aisles, gun in hand. Nardole jumped in surprise. "I wouldn't go down there. He's definitely dead." She looked down at the gun. "By his own hand."

"Well, that answers that question," he replied and she nodded.

"Not a single person who has read the Veritas in the Vatican has survived. I wonder how CERN are doing with it."

"Do you think they'll kill themselves as well?" Bill asked and Danni nodded.

"Most likely. We need to find out what that text says. I wonder if the Doctor has read it yet."

"He said he wouldn't until we got back."

Danni shot her a look. "And you believed him?"

Bill opened her mouth to protest when the same blue light from before illuminated them all.

"It's an opening, like we saw before," Bill breathed.

"Yeah, like a portal," Nardole agreed with a nod.

"Or a door," Danni added before walking straight towards it.

"Ma'am, wait!" Nardole exclaimed. "The Doctor won't be happy if you step into that!"

"I don't really care if he's happy or not," she snapped. "If he wants, let him complain. Maybe someone else will listen."

"You know, for his wife, you say some weird stuff," Bill pointed out. "You never seem to care."

"You're right, I really don't," she retorted. "I've walked through many doors that shouldn't exist in my time, and the truly bad ones always have one thing on the other side. Eventually they all lead to the same place and I am going to follow this until I find it."

She stepped in the light and Bill looked over her shoulder. "Should we follow, or go to the Doctor?"

Nardole was torn, but ultimately his vow gave him only one option. He nodded towards the portal and the pair followed her inside.