The Doctor rather enjoyed sneaking into the ridiculously named 'Hub'.

He never got to sneak anywhere these days. He was decidedly less happy to have several humans waving silly little guns around burst into Jack's office once they finally noticed, where he was patiently waiting in the chair. "Oh put them away, you'll scare the poor pteranodon."

"Oi! She has a name. Who the hell are you?"

Jack had put his own gun away on sight, glaring at him. The Doctor spread his own hands "That's not a very polite way to greet people." The man looked at Ianto like a child who forgot to say please before focusing his full attention on their Captain, "Hello Jack. I brought pizza. I think it's the right ones, unless you're tastes have changed." He laced his fingers together, raising bushy eyebrows.

"Not as much as you have I think."

"Ah. We're then. Ok. That's good to know."

The captain lowered voice, "How is she?"

The Doctor's voice was flat as he answered, "Gone."

He didn't need to explain, Jack would understand. He wasn't about to start sharing with the class.

"I was beginning to think you weren't coming back. Everything said you were close but you don't write, you never call, I even wondered if the instruments measurements were wrong." There was so much unsaid between them.

"I was busy." The Doctor's eyes clouded over.

"You know him, Jack?"

He flashed a smile at the woman asking, "We're old friends. He and I go way back."

"And here I thought it was forward." The Doctor raised an eyebrow at Jack's quick response.

"Any way you want. Put the guns down kids, and help yourself, the food's safe. Poisoning isn't his style."

Owen glowered, "No offence Jack, but we're a lot more concerned about whether explosions and psychotic power trips are than the toppings." Jack stared at the slim man until he grumbled and holstered his weapon.

The Doctor looked up at his friend, the haunted look was still there, easy to see if you knew, but there was a happiness that had been missing the last time they met. "It's a nice family you have Jack."

He smiled, "Nice probably isn't the word, at least one is an asshole; but they are brilliant. Fantastic. Important." The captain nodded towards his friend. "I like this face. It's very… expressive. Maybe a little too mad professor for me, but it works on you.""Mad professor?" The man looked outraged.

"Yeah." Jack grinned manically, before he settled into sterner lines, "Seriously though, Doc, how do you feel about explosions this time? It is something your feelings have been different on from time to time. The last face notably coincided with quite a number of them, the first one I knew, well..."

"Last face?" Mouthed Gwen, and the Doctor's brows knit together,

"Hey, you're the one working for a man who can't die- well, stay dead, isn't it strange how his face is the same every time he comes back? No? No one finds that weird?" The Doctor looked around the room and found similarly puzzled faces to Gwen's.

Jack rolled his eyes, "Doctor, in the most disappointingly boring sense of the phrase, can we take this to my bedroom?"

"Oh! You have one of those now? Does it have bunk beds? Or algae beds- no, wait, wrong century-"

"Nope, just a normal one I'm afraid, very dull, but I don't sleep much anyway, you coming or not?"

The Doctor looked over Captain Harkness, confident as ever and in control, and removed himself from the man's seat. "Well it has been a long time since an intriguing man invited me to see his bedroom, how could I pass up an offer like that?"

Catching the flash of jealousy on Ianto's face Jack rolled his eyes, "Relax Yan. Nothing to worry about. I'm not his type." Jack winked cheekily at his boyfriend as stalked out of the room, followed by a man who looked more grizzled than any who had visited so far.

The Doctor looked around him on the way down, it was odd what people found comforting.

The bedroom door swung closed behind them and Jack let go of his persona, whirling to face his oldest friend, "What the hell, Doc, where have you been? The last time I saw you, you had a different face, voice, everything, what the fuck happened?"

The Doctor closed weary eyes and almost breathed his answer, "A battle. A very, very long battle. I found them, and they could have returned. On this side even the Papal mainframe fell. There was a lot that happened Jack, and too much that was lost. I shouldn't even be here, the High council limited our regenerations, and for good reason, of course most Gallifreyans get longer out of each than I did, but that's beside the point. Anyway, I'm stuck here now, because of one of the reasons they can't just have us running about as the next thing to immortal, I've been guarding a friend. Nemesis. It's complicated. I didn't tell you before because well- I'm rubbish at that, and you two have a history, but I have a guard duty for another 900 years; so I guess this is home for now."

Harkness narrowed his eyes, "Who told you that you were being rude by not saying hello, Doctor?"

"You wound me Jack, why could I not simply decide one day to visit an old friend?"

Jack rolled his eyes, exasperated. "Doc, I will fill your deceptive pockets with treats for Myfanwy and send you out without a water-gun." One bushy eyebrow shot up,

Jack smirked, "She's like a cat that way."

The Doctor nodded his understanding. "Fine. Merlin is in town - in my defence, he didn't exactly turn up on his first day teaching either."

"Uhuh. I knew it.. But Teaching? When did you become a teacher again?

"About 95 years ago. Keeps me sane. Er. Plus they have brilliant basements in universities and expect everyone to be eccentric. It's like being invisible."

"Eccentric. Right. And Merlin is not here with you because… ?"

"I'm telling him that you think he's eccentric. He is marking essays, officially. And doing me a favour. Name one other person you'd trust to inhibit a Time Lady."

Jack grinned, "He knows. Told him myself and he tied me up with that neckerchief of his to prove he has reasons. It didn't help illustrate any less eccentricity. Besides I'd be more worried if a man like him seemed normal. They'd be secretly plotting something nefarious."

"Well of course they would. Even you must get bored. I am almost certain he is anyway, but at least he is not in favour of world domination."

"And you are choosing to leave him with someone who is?"

The doctor frowned, "Well maybe a little bit…"

"Is she pretty?"

"I think so, but I'm not impartial this time."

Jack rolled his eyes, "We're doomed."

The Doctor looked unimpressed, "Like you would be any better Jack."

"Fine; we might be doomed."

"Humanity is always doomed, always in danger, so fleeting. Nothing lasts forever. Where does obsessing over the inevitability of an end get you? All we can do is help them." River, the Ponds, Tasha, Clara, all the endings fluttered around the edges.

"You've forgotten who you're talking to, haven't you." Jack Harkness didn't wither and fade like other living things.

The Doctor frowned, "Even you Jack. There is an end to all things. Or an undoing. Depends how it's done. Time's like yarn, so many things, events, creatures to create with it, and then the stitches torn out to be remade as something new. You never know what the next masterpiece will be."

"I'd ask you what that's meant to mean, but I suspect not knowing is kinder."

"I've a pupil who'd interest you you know, already completely convinced you and UNIT exist though she's no idea of the names. Couldn't afford university so got a job in the cafeteria and started sneaking into all my lectures- others too, but saw inconsistencies she shouldn't. You'd like her- though not like that, she's ah, pickier than you."

"Hey, I'm everyone's type."

The doctor's gruff laughter rang out, "Not hers. Though I'd give much to watch her take the wind out those sails."

"Ah, that kind of picky."

"Oi! Don't say that like it's bad thing. If you were anyone else it'd make her life expectancy better than yours."

Jack chuckled, "You're not wrong. So Merlin took up teaching again? He hadn't decided last time I saw him."

"When was that?" The Doctor inquired, the man hadn't mentioned how long he'd been doing it this time.

"Which Merlin?"Jack arched a brow and leaned back against a support with folded arms.

"Oooh he and I will be having words if he is mucking about in time again."

The captain frowned, "I don't know Doc, it didn't seem to be intentional and he looked pretty shocked just appearing there, damn I hate when he does that. At least you have the courtesy to bring a ride and make waves on the rift monitors."The doctor spun around waving him off, "You are not making it sound better Jack."

"Do you really think he'd tell you if something was wrong before he could explain what it was? New face aside you're not looking at your best. If I can see it, he could. Anyone special?"

The Doctor scanned Jack face as carefully as the sonic would.

"You told me a long, long time ago Jack that everyone should get a last night. The ones that matter most. I ran from it for centuries, trying never to use it up, but that 'last night' finally caught up to me." Old eyes met their equal;

"Where did you go?"

The Doctor smiled softly, "Somewhere she had wanted to visit almost as long as I knew her. Darillium. They built the place for us to watch simply because she wanted to see the Towers sing. In the spot we first saw them. She would go on to see me one more time, but it wasn't me. I would have done almost anything to be the one to answer, but I swore to River I wouldn't change anything, before I knew what I was doing. That woman knocked me sideways from the start, when I was still so far away from the man she needed. We had the last night though, oh and it was the best night Jack."
"You know the way I hear it, night on Darillium lasts longer than on Earth."

The Doctor huffed "She hit me for that."

"Sure she did." Jack snorted.
"I'm serious. Don't tease archaeologists, they're violent."
"You know she was never particularly subtle about that part, it was even part of your elaborate mating ritual flirting. If that was a surprise to you I'm on her side."
"So you should be Jack. So you should be. If you ever do see her again, tell her I'll always be coming home. Give her a hug. She never did get enough hugs, she'll trust them from you."

"Not unless I try and kiss her. She'll just assume a shapeshifter"

The Doctor twitched, "Fine. If it means she gets a hug I won't even glare. Can't see River taking it well if I ever told anyone which boundaries should be respected. If she doesn't like what you're doing, she's the one who'll shoot you."

Jack rubbed a phantom injury, "She did. Quite right too, we weren't on the same side that time."

"It's big old universe Jack, but just occasionally you get a beautiful coincidence."

He chucked, "Yeah. I always do keep an eye out for an mutual friends."

"Have you told Merlin about the pterodactyl?"

Jack's face twisted into a mask of horror, "OH FUCK! I haven't"

"You are seriously telling me that you let me meet your pet pteranodon before you introduced the dragonlord. He thought I was being rude. Good luck explaining that one."

"It's a pterodactyl, not a dragon, and it's not my pet, it's Ianto's."

"It has a name, an inside roost, you give it treats, and I really don't think 'it's my boyfriend's' is going to get you off the hook. It'll be interesting for science though to find out whether the two species are related, I wonder if Myfanwy would listen to Merlin. Not sure what he'll make of the name though, he has…. Opinions, about those."
Jack laughed, "I know what 'Aithusa' means. I'm pretty sure he'll approve of Ianto's possibly over romantic choice. If there is a second man on the planet who can look at lost and defensive pterodactyl and think 'beloved', Merlin is he."

"So what now?"

Jack shrugged, "I have the coffee of the gods, and night shift, but you've got itchy feet and said the rift monitor is uncomfortable, unless this you doesn't feel that. It's ok, I get it. You know where I am if you ever need to be not alone. Just make sure the food wasn't a one time deal. Take away gets you everywhere with this lot, actually most food does. Ianto's the only one who can make anything edible."

"Fine. I'm not bringing ice cream though. Or sending postcards. Amelia Pond had us stopping to get specific tubs of ice cream."

"Hmm. Figures. I rather miss Rory you know. He was like a real life handsome prince except that he wasn't an asshole when you got to know him."

"Aye. So do I. He was a good man. Do you think there's any chance they'll believe I'm a student if I turn up at his lecture in the morning? Last regeneration was easy." The Doctor frowned.

"Mature students are a thing now. They might believe it, if you weren't already on retainer. Or if could keep your mouth shut. No trolling each others classes alright? If I get called in because you pair are pissed or disruptive I will be Very Unhappy." Jack mock- glared at the Doctor, who smirked back,

"Well, if you throw a hissy fit over it I'll let you explain to the federal board of interplanetary governors next time someone accidentally assassinates an over inflated runaway rich girl."

Jack groaned, that had been a Bad Day. "It was hardly a negotiation, and she had killed over 30 men by then, completely aside from the gaseous form being hard to imprison."

"I don't disagree, but you were not authorised. Swings and roundabouts Jack. Fine. No trolling. No other promises though." Jack moved to hug the Doctor before he left and the timelord went awkwardly stiff. "Not a hugger this time then."

"Ah, no. I don't seem to be. Probably used up the full quota on last regeneration."

Jack hummed. "You were very tactile in that body. Not that I blame you, but Doctor, take care of that face. I plan to see what those eyebrows can do before you trade them in."

The Doctor smiled, calling back to him, "Don't damage that coat. Getting hard to replace now without someone noticing."

With his pockets pterodactyl food free he left the Hub, and Jack Harkness behind.

Merlin glared at the paper in front of him. It burst into flames. Fuck. That wasn't supposed to happen any more. He rearranged the atoms into their previous placements. He almost missed not knowing what he was doing. It seemed less weighty then.

Missy. Who was Missy. Old friends, Timelady. Couldn't be Susan that much he knew, Ramona wasn't here now, was she, or the walls of reality would have collapsed, unless that was why he was slipping again. Possibly her then? Definitely not River, he'd never imprison her again. Something niggled in the back of his mind. Missy was a daft name for a Time Lady, it had to be short for something, and most people dropped the ending rather than the first part of a name. Mistress maybe? It certainly worked as a title. Better than the Mystery or The Misfortune.

Running back through what the Doctor had said he remembered the mixed pronouns and realisation dawned as he half shouted,

"OH FUCK! That sentimental fucking bastard has the Master in the basement."

Maybe this version believed in rehabilitation. He still needed a skelp for utter stupidity. Merlin had lived through enough of the Master's schemes, evil plots, and games to know what he was dealing with. He no longer registered as Human enough for the transformation targeting them to work. Missy was as unhinged as Morgana.

Still, like his 'it's complicated' she wasn't ever boring.

At least the strict warnings made sense now.

Who kept a bloody psychopath who turned planets into warships next door? The Warlock sighed, stupid question; of course the Doctor would.

He did seem to have a soft spot for them though, and Merlin wasn't best placed to judge either saviour complexes or tangled relationships with nemeses. Or unwise soft spots.

As soon as the marking was done Merlin went looking for his Time related magic books. The most inconvenient thing about Timelords- and Ladies- was their ability to sense when he was messing with it. Slowing it, pausing, speeding things up, rewinding, creating little bubbles, they were aware of all that like he was, remembered it all, it would be of no advantage to him, and they could use it. Use him; much as he hated to admit it.

It was a long night for the man as he considered what types of shielding might be useful, and which types of energy the Master- Missy might be able to manipulate. If she wasn't a sadistic, power crazed megalomaniac serving a millenia long prison sentence, she could be fun to play with. If he was willing to risk reality for kicks it still could be, but even he wasn't that bored yet. Arthur would be pissed if he destroyed Albion in his absence too. Maybe enough to wake up to come and throw things at him… No. Bad Merlin. Fate of the world over attempts to wake old friends. Always.

At least Missy didn't know about the dragons, that would be bad. She might know about the faye, they were fewer now, but Earth didn't only house humans. They were just the most obvious. Something, or somethings dwelt under the surface but he'd never had cause to seek them out; the Doctor might know. Whether asking was wise or not was a different question.

By the time the sun rose Merlin had some ideas, and a reinforced mental wall. Telepathy was supposed to be something most of the Master's incarnations excelled in. Not a risk worth taking if that's who he was dealing with.

Early lectures were often a blessing to a man who rarely slept anymore, he tried. He really did but sometimes he'd wake up in the wrong place, or the dreams, or visions, or nightmares would come. It wasn't always a good idea to sleep.

The looks of shock and horror on young faces as he explained the consequences of poor infection control, and certain procedures was both amusing and saddening. He'd seen the difference antibiotics really made. They changed everything. He'd lost more than a few friends to now easily cured diseases. The only thing that got the exact same reaction from his listeners was the series where they covered the history of contraception. That tended to have an effect on quite a few students.

Seeing the Doctor sitting near the back he grinned, it was rare that he had anyone who could refute or properly understand the practices or argue with him. Even rarer to have someone who had seen it done or developed. Thankfully he kept any opinions to himself for the hour, waiting until the students had left.

"Interesting. Are you ever going to have them attempt making the remedies, or non harmful practices?"

"Not actually a bad idea for workshops. Do you think anyone would try drinking it? They're a lot more drinkable since those flavouring syrups went mainstream. Doesn't stop them working."

"You've tried?"

"I'm not a saint Doctor, and most people don't want to think they went home with a crazy person, or work with one. 'Here, drink this. It's a Family Secret' works a lot better the the offer of a spell to instantly cure hangovers." The Doctor nodded an acknowledgement, Even he cringed at the offer of a 'spell', though not because he doubted the efficacy. He knew from experience that it worked as well as his own detox options.

"I'm gonna assume that's also not ok for Missy, if alcohol even works on her."

"Definitely not. Drunk Missy is….less restrained."
Merlin nodded. "So why are you guarding the Master this millenium? I thought you were in a stable enemies phase last time."

"Long story Merlin."

The man gave him the warlock eyebrow, "I'm not short of time. Ever. You're pretty when I hold you up to the energy, like a prism. Is it a Timelord thing or just you?"

The Doctor cursed. "Timelord thing. Don't try to look, you shouldn't mess with the strings, Bad Things can happen then."

"Promise. No matter how tempting it is to pluck them. Does it sound like music?"

His friend growled "I don't know, it's on the list of rules that are serious enough to not break. They did it during the war, I have no idea what could happen, and neither do you."

His eyes softened, the war was a subject that the Doctor rarely mentioned now and tried to avoid. "Long story for your office of mine?"

"Mine." Was the Doctor's clipped answer.

"You did the thing I told you to?" Merlin knew the answer but it was a deliberate change of direction the the Doctor would appreciate. "I saw him. Turns out he owes you an apology of his own."

Merlin grinned. "His flighty pet. Aye, I've met him. He promises to be well behaved as long as they are. Jack is not his favourite. Apparently he smells funny."

His friend laughed, "Well that answers that question."

"Don't tell him I know, I want to see his attempt to apologise for neglecting that one. It's not the same as a dragon, that's like calling a house cat a fucking tiger. Still, more interesting than most of their other visitors, and he listens well."

"Not a word. Ah, here we are, there's a kettle on the side, behind the big chair." Merlin rolled his eyes, fifteen hundred years and the man still forgot that it was unnecessary, though in company he usually used them anyway. Tea was one thing he did appreciate these days, along with medicine and spices. He missed his land, but at least this one had some compensations. Indoor plumbing was pretty good too.

"I didn't tell you she was the Master." The Doctor frowned, this face tended towards that.

"She isn't, she's Missy, it's a stupid title. Short for Mistress I'm assuming. Been a while since I saw him, that was not fun. Good thing someone stepped in to save the day."
"You stayed out of that one."

Merlin shrugged, stirring his tea, "Wasn't my fight, you were both here, I'd just have been in the way, and an added complication to plans. Better I hid the dragons. The body heat shows up something terrible if I don't disrupt the scanners. A lot less destructive than most missiles, but great for spreading terror. The TARDIS was screaming, and they wanted to help her. It's complicated."
"Isn't it always." The Doctor looked round at the appearance of what seemed to Merlin to be a talking potato. "The prisoner wishes to speak with your guest."
"Tell her no." Merlin levelled a glare at the Doctor for answering in his place. "I'm perfectly capable of making my own decisions about safety thanks."

Shaking his head the doctor ran fingers through his hair, "You asked for the story first. Best you hear it before speaking to her."

"Bit late for that, she's not quiet. Has she been talking at you the full century? Gods, it's just as well you lost the right to claim full sanity years ago. That's enough to tip anyone over."

"Not quite. There are dampeners up anyway."

"Not enough Doctor. Mind me putting a silencing charm around here so I've a choice? Man, she can bitch."

"Go ahead if it's still bothering you. She's had a lot of practice."

Relief flooded Merlin as he did so."Yeah, but at least she isn't broadcasting drums this time, thankfully. That was deeply unpleasant."
"Yes it was. The cruelty of the council has had far reaching consequences." The Doctor sighed and Merlin's face went blank "Cruelty always does."

The Doctor saw his friend's ashen face, bad year then.

"Don't do that, I'm fine, great even, could use a distraction. Just one of the dates that are dark."

The Timelord frowned, there were too many bad dates in the warlock's long life to know which this was, his thoughts were interrupted, "Doctor. Please. Distract me, not dissect me. Does Missy know you plan to hop off world?"

He considered it, "Possibly. I hope not, but she's probably more surprised I stayed still this long. Maybe I'm growing patience."

The warlock snorted, "Patience? You?"

"It could happen." Insisted the timelord.

"Of course it could. So could the collapse of the Himalayas, and the third big bang." Surprise showed in the Doctor's eyes and Merlin laughed,"Oh, come on, did you think I wouldn't notice the rejig? You're as subtle as a brick to the face that way. It's good work, you get points for the artistry."

"Honestly, I didn't, You shouldn't have known Merlin. Something is...wrong. You cannot ignore it forever."

"I don't intend to, but one more day isn't going to make a difference. After your trip we'll talk, but first take the new girl to see something amazing, give someone an overdose of joy and adrenaline for me. You're avoiding how you acquired the Master- um Mistress. Gods that sounds unnatural, Milady, My Lady, even Ma'am I could work with but Mistress? That's just for a proper Domme, I'd always be looking for the crop. 'Missy' was a good call on her part."

"Don't expect any more mercy than you would from any of them."
The old warlock pressed his lips together thinly. "I've met him before Doctor. You aren't always on time, none of us are. Mercy isn't her strong point; but mine is slipping too. Maybe I should try it your way some time."

"You said it yourself, you can't hide again, however you make it work, as long as it isn't lunch dates with Missy."
"Aww, and there I was hoping to co-conquer the universe. Gods no, I've seen the paperwork with high positions. No thank you. Your dinner lady's cracked the system already. She's just using you for your motor." Merlin winked at the Timelord.

"Even if she was, the theories she opts for are more imaginative than most of them come up with. Worth it."