Sherlock usually had no patience for human drama or emotions or sentiment or any of that. (Hadn't his speech at John and Mary's wedding proved that?) But this? He could almost admit that this … reunion … was fascinating in its way.

Now that he knew more of the facts, the genetic ties between John and his grandfather were more obvious than ever. The similarities that had been nagging at him before suddenly made sense. The height, the nose, the tea preferences … though that last might be purely circumstantial. He would really need some kind of blind testing to confirm or deny that hypothesis, and obviously the data was already skewed.

He was sure there would be tedious details to work out, going forward. DNA tests, getting proof of the marriage from Las Vegas … along with proof that it had not been annulled or otherwise legally concluded.

…And wasn't that interesting, considering the Earl's son had gone on to get married again here. Because if the original marriage to John's mother was still in effect, that made his second wife … not his wife. And now it was the daughter who was illegitimate, not John. (Because, really, how could John be illegitimate? He was the most honestly straight-forward man Sherlock had ever met.)

The two of them were still comparing notes—dates, times, names, and so forth. It was as if neither could truly accept the truth without massive amounts of unnecessary nattering over the facts. So Sherlock turned his attention to the original purpose for coming here.

If the earl was being blackmailed for his son's youthful indiscretion … an indiscretion for which Sherlock was forever grateful since it had led to John Watson's very existence … how would his meeting John affect it? The earl had said he thought the blackmailer believed he had known the truth. If that were true, his having called Sherlock and John to the case was serendipitous, because it would look like, in his panic, he had directly called his bastard grandchild—presumably to make amends or excuses or some such thing as a pre-emptive strike.

Which would have been logical … except it wasn't remotely true.

No, the earl had acted innocently, from a desire to find the truth and do the right thing by a grandchild he didn't know existed.

Sherlock had to admit, that was unexpectedly … heart-warming.

He looked back at the other two again. They were talking now about John's service in Afghanistan. Dull. (Or, well, maybe not dull in itself so much as dull because Sherlock already knew about it. It was old information, unlike the revelation about John's biological father.)

Did the blackmailer know John's true identity? If he knew enough to be aware of John's existence, he would almost have to know his name. But did that automatically mean that he knew where John was now?

There was not enough data to speculate, but probability was that he did. Why draw attention to a person if you didn't want the attention?

So, what then, really, did the blackmailer want?

"…Sherlock?"

He blinked and refocused on that pair of matching, amused faces again. (Really, the relationship had literally been staring him in the face since they got here.) "Hmm?"

"I asked if you thought the blackmailer knows about Dr Watson?"

"I think he must," Sherlock said. "The question then arises—is he trying to blackmail you? Or John? Because I feel reasonably certain that this is not the act of a good Samaritan trying to draw attention to a long-neglected grandchild."

"Yes," the earl said, shaking his head. "I'm afraid I must agree."

"Or…" John started, then paused. "You said my fa… your son was married? But if he was married to my mother and that was never annulled … that makes him a bigamist. How could he do that? Aren't there … checks … for that kind of thing?"

"It's not supposed to be possible, no," said the earl, thoughtfully. "Unless your mother did have it annulled and just never told you? Protecting you, somehow?"

"It's possible, I suppose," John said, tilting his head as he looked at the photo in his hand. "She never really said much about him, just that it had been an impulse to get married—they'd only known each other a few days and alcohol was involved…"

"Las Vegas does have a certain reputation," the earl said, voice dry. "Even then."

"True." John smiled at him, but then sobered. "I asked her once, why it didn't work out. She just said it had been a mistake, that he'd been called home, and they were never meant to be. She tried to forget it, I think, so I didn't press. I've wondered, over the years, if she tried to find him when she came back to England when I was three, but she never said."

"When you were three? So that would be, what, 1976? That's the year Jonathan got engaged to Margaret."

Sherlock's eyebrow lifted. That was an … interesting … juxtaposition of dates. John appeared to think so, too, leaning forward eagerly. "Really? That's … a coincidence, isn't it?"

"Perhaps they met and took care of any necessary paperwork then, quietly?" Sherlock suggested.

"It would make sense," John said thoughtfully. "A few legal papers to end the marriage and then going their separate ways? It's not like they were a love story for the ages, or anything." He rubbed the back of his head again, absently.

"Are you all right, John?" the earl asked, eyes concerned.

"What?" He blinked and then nodded. "Oh, well, yeah. It's just something of a shock. I mean, I knew about their spur of the moment wedding and the fact that it didn't last, but I never realized that they'd only known each other for about a week. Essentially, I'm the result of a drunken fling."

"With marriage lines," Sherlock put in.

"Oh, well, sure. That makes all the difference," John said, trying to joke. "Though if Mum and Jonathan met to sign divorce papers when I was three … I wonder if she told him about me."

There was silence for a moment, then the earl said, "For what it's worth, I don't think she did. My son wasn't perfect, but he cared enough to marry your mother—however briefly—and he would have cared about you, too. He wouldn't have abandoned his son."

"But if he was getting married, starting a new life…"

"He would not have abandoned you," John's grandfather said firmly. "I'm certain of it."

There was silence for a long moment as John nodded, trying to convince himself that the older man was telling the truth. Because, really, how could he know for sure? People do unexpected things all the time. Sherlock's entire career was essentially based on the fact that everyone has secrets and they almost always fail to act rationally—but the earl believed that he was telling the truth, so for now, that was what mattered.

"So," Sherlock said as the moment lengthened. "We need to determine whether John's parents got divorced, and it seems that the time from her return to England to Jonathan's marriage would be the likeliest time frame."

"Agreed. We need to find out. Especially … especially since, if my parents' marriage stands, that makes your granddaughter illegitimate, doesn't it?"

Interesting. Sherlock hadn't thought about that angle. Was illegitimacy really something people worried about in the 21st century? Lord Undershaw was shaking his head, though. "Oh, poor Harry. This will devastate her."

"Really?" Sherlock said, but at John's glare immediately segued, continuing another train of thought. "So, that leaves a number of possible angles for your blackmailer. And, of course…"

He broke off, mind racing. If the blackmailer had known about John's current whereabouts and was aware of his partnership with Sherlock, he could theoretically be meaning to apply pressure to John himself. Or Sherlock? Maybe Mary?

Too many variables.

"Do you know anything about the blackmailer?"

For the first time, the other man's face froze, closing off the open expression that had made him so seem so similar to John.

Interesting. "You know him."

The face grew even tighter. "He is not a man to mess with, Mr Holmes, and I'm not asking you to do so. I needed help finding out whether his accusations were true—a task you helped me with quite handily—but you need not involve yourself further."

"No." John's voice was quiet, but in the silent room, it may as well have been shouted. "You asked for our help."

"For a fairly simple investigation," the earl said, "Not to take on Ma…"

He caught himself, but too late. He'd already said enough. "Magnussen," Sherlock said.

The old man's eyes closed as he nodded. "Yes."

"Wait, who?"

"Surely you've heard of the media magnate, John? Except he does more than just publish the news. He collects it—every dirty story, every pressure point … in some ways he is the most powerful man in Europe because he holds something over almost everyone. He is the Napoleon of blackmail. I've gone after all sorts of criminals—kidnappers, serial killers, more than I can mention—but nobody turns my stomach like Charles Augustus Magnussen."

"So you know the man, then," Undershaw said. "I'm almost afraid to ask if it's from personal experience or not."

"Not directly, no," Sherlock said. "Though I have … friends … who have tangled with him in the past."

John looked surprised. "You do?"

Sherlock gave a mental sigh. Did John not pay attention to anything? Didn't he remember the telegram from CAM at his own wedding? "Of course, John. Do keep up." He looked back at the earl. "The point therefore remains—I would be happy to help you."

"I wouldn't ask anyone to tangle with Magnussen, Mr Holmes."

Sherlock smiled. "How fortunate, then, that you don't need to ask. After all, my lord, if you are John's grandfather, that makes this something of a family affair, doesn't it?"

#

John climbed out of the cab at about half the speed he usually did. All he'd done today was go and drink tea with a perfectly nice old man who happened to be an earl. Why was he so tired?

But then, he supposed life-shaking news like discovering said earl was your grandfather could take a lot out of one.

He was just aiming his key at the lock when the door opened in front of him. "You're home!"

"And glad to be here," he said, stepping up to claim a kiss. "Sherlock and I have news."

Mary's eyebrows lifted, but she just stepped back, pulling the door wider. "Then come in. Tell me."

The three of them went into the sitting room and John wondered yet again how he was supposed to explain any of this. He sat down on the couch, pulling Mary to sit alongside him, taking comfort in her familiar presence. "Sherlock brought me along to meet a client of his today."

"About time, too," she said. "You've been moping around here for days."

"Right," John said, not wanting to get side-tracked, arguing about the definition of 'moping,' since he certainly had not been. He'd been enjoying his newly-wedded bliss, hadn't he? "The point though…"

Christ. How was he supposed to explain this? He looked over to Sherlock and immediately worried that his friend looked all too ready to jump in with his own explanation, and who knew how that would go, so he looked over at Mary. "You remember how we were congratulating ourselves while planning the wedding? About how lucky we were not to be burdened with family we wouldn't want to invite?"

She nodded.

He took a breath, fingers gripping hers, and then said, "It turns out … I may have some after all."

"Really? Who? Wait … your birth-father? You found him?"

"Indirectly. It turns out that Sherlock's client is … was … his father. Which makes him my grandfather."

"John! That's marvellous!"

"Yes and no," murmured Sherlock from where he sat with his hands steepled under his chin.

"Yes and no?"

John spoke first. "Well, one, my father died a few years ago, and, two…" His voice trailed off. Really, how was he supposed to explain this?

"Two," Sherlock said, "His father, John's grandfather, is being blackmailed over Jonathan's indiscretions—namely John."

"Except it wasn't really an indiscretion since he and my Mum were married," John quickly added.

"You've told me that," Mary said. "He abandoned her, didn't he? Before she moved back to England and met Bert?"

"Well, apparently he didn't so much abandon her as he was ordered back to the family business and didn't bother to enlighten anyone as to why he wanted to stay in California. I don't know if he thought she'd annulled the marriage or if he'd forgotten they even were married…"

"Forgotten?"

"It was a Vegas wedding, remember? One of those chapels where you can wander in and tie the knot, no matter how drunk you are?"

Her face fell. "Oh. Right."

"So, anyway, it's possible he thought of her more as a fling than as a wife. It's also possible that my mother did annul it and just lied to me to spare my feelings. And then there's my favourite possibility—because of the timing, it also seems possible that they met after she returned to England and signed divorce papers that we don't know about yet." He twined his fingers into hers and sighed. "About the only thing I'm reasonably certain of is that my father never knew about me at all—and that, regardless of which one is currently legal, he actually had two marriages."

"And now he's dead and can't answer any questions?"

"Yes," Sherlock replied. "And the blackmailer is apparently applying pressure, claiming John's grandfather has deliberately been keeping this knowledge quiet to keep John from his inheritance."

Mary's face lit into a delighted smile. "Inheritance? Have I inadvertently married into money, then?"

"More than that," John told her. "Apparently there's a title involved."

"A title? Like what? 'The Case of the Mysterious Drunken Wedding'?"

John tried to laugh. "Not that kind of title."

"More like, Lord Brandon, Earl of Undershaw," Sherlock put in helpfully.

"Earl of …" Mary's face went blank. "No."

John nodded. "Yes. I mean, there are proofs needed and DNA tests to do, but since my father died, apparently this makes me next in line for a hereditary title I knew nothing about. A terrifying thought, isn't it?"

She tipped her head. "Well, yes, but … on the plus side, I suppose this means we'll be able to afford childcare now?"

Now John did laugh, putting one arm behind her and pulling her in to rest on his shoulder. "True."

They sat in companionable silence for a few minutes, before she asked, "So, what's your grandfather being blackmailed for? Did he know about you?"

"He says not," Sherlock said, "And I believe him. It's anybody's guess what Magnussen wants."

John felt Mary stiffen in his arms. "Magnussen? Not the…"

"Media mogul with the initials C.A.M? Yes." Sherlock was watching her keenly now and John suddenly felt he was missing something.

"I wonder if that's how he gets his stories," Mary asked. "Digging for dirt and hoping to find some?"

"Possibly," Sherlock said. "Or he uses the secrets he does know to get what he wants."

She relaxed back against John. "So, what does he want from John's grandfather?"

"That's apparently the question."

"Really," said John, "There are a lot of questions."

"Sure, not least of which is, what did the earl do when he found out who John was?"

"If his legs had been up to it, he would have danced a jig," Sherlock told her. "Apparently he has longed for a grandson for years."

"Hmm," sniffed Mary. "Maybe he should have looked for one, instead of leaving John to struggle on his own."

John just hugged her tighter. "Now, Mary, if I'd been raised as a member of an Earl's family, I would never have been working in the clinic where I met you."

And then he laughed, because the thoughtful look on her face was irresistible, even if Sherlock didn't look particularly amused.

#