Henry preferred to work alone, and if that could not be managed, he preferred to work uninterrupted. If that were impossible, he preferred to go home and come back and do it another day, except that he was no longer a gentleman physician, at liberty to practise or to stop: he was an ME employed by New York City, and that meant that even on a day like today, he could not simply throw down the latex gloves and leave the deceased to the care of whoever interrupted him. All of these facts meant that he now had to suffer the presence of this talkative, self-proclaimed crime-resolution expert.

Somehow it made it worse that the fellow was also an Englishman.

Henry sent despairing glances around his examination lab, but there was no respite. The loquacious man, some sort of private detective under licence to the NYPD, was clearly here to stay.

"Clearly murder," the fellow was saying. "You need only look beneath the fingernails to confirm that there are traces of human skin trapped beneath them. This man fought for his life before, according to the police, he slipped in the bathroom." This statement was accompanied by broad hand waving and the generous use of air speech-marks.

The speaker's companion rolled her eyes. "Dr Morgan knows that, Sherlock," she said.

Henry looked at her gratefully. She was a slender woman of Asian appearance: Oriental, they would have said in his day. She had bright dark eyes and a smattering of freckles over her fine features. And although she was dressed in drab grey jersey tunic with lumpy hose and practical winter boots, Henry thought her beautiful.

"My apologies," said the interloper now, extending his hand. "I am a man of many endings but I am very bad at beginnings. Allow me to introduce myself. Holmes, Sherlock Holmes. This is my partner, Joan Watson."

"I agree with your conclusion, Mr Holmes," Henry said. "And I would go further. Our victim knew he was going to die. Look." He peeled back the sheet covering the dead man's torso.

Holmes grunted.

The dead man's chest was covered in writing.

"Ballpoint pen, not tattoo," said Joan Watson, peering in. Henry saw at once that she was a doctor like himself, but specialising in life, rather than death. Her hands were swift but precise. She began to make notes on her tablet. He approved.

"What strikes you about it?" Henry asked her.

"It's ...smeared and blurry..." said Joan. "Done in a hurry."

Henry nodded. "And upside down."

Holmes frowned. "He wrote it himself."

"Indeed," said Henry.

"A living will," said Joan. She read aloud. "'I wish my possessions to be given to the poor. But the diamond encrusted box belongs to ...'" She squinted at the awkward lettering.

"G Logan. " said Henry.

Sherlock was already tapping furiously at his phone.

Henry said, "Our victim knew he would be killed. Perhaps he even heard his attacker coming and ran into the bathroom to hide. He snatched up a pen, wrote this expression of wishes on his own body -"

"I guess you don't take paper into the shower," said Joan.

"Exactly - and then he put his shirt back on before the murderer arrived and dashed his head repeatedly against the corner of the bath. A very painful way to die, believe me." Henry grimaced at Joan. "The diamond encrusted box must have been very important to him."

"Or G Logan was," Joan said.

Henry shrugged. "Perhaps." Living as he did, it was easy to forget that most people had friends, family, lovers. He had known too many endings himself to pursue those things any more.

"G Logan. Gina Logan. " Sherlock said, holding up his phone to show them a young woman with blonde hair and a smirk. "Our victim's business partner. They own an antiques shop, and she lives there."

"So where's the diamond box?" said Joan.

"Not in the victim's apartment," Henry mused. "The police searched it top to bottom."

"The murderer stole it, obviously," said Sherlock. "So our task remains the same: find the murderer. We will also find the box and return it to Ms Logan."

"Something about these skin samples troubles me," said Henry. "The texture..." He tailed off, frowning.

"I'm more disturbed by the wording of this so called living will," said Sherlock. "Diamond encrusted? A phrase guaranteed to grab the attention, don't you think?" He raised one eyebrow. "I propose we pay a visit to Ms Logan. Dr Morgan, will you join us?"

"I ought to get back to my...roommate," Henry said. "He's rather elderly, and none too steady on his feet these days. I'm worried he might try to bake cinnamon rolls."

"What's wrong with that?" asked Joan.

Henry smiled. " I need to discourage him from climbing. And he knows I keep the cinnamon in our highest cupboard."

"You must be like a son to him," Joan said.

"I don't really think of him like that," said Henry. Sherlock gave him an odd look. Henry was used to it. No doubt it would be easier to allow people to think he lived with his old dad or uncle. But his was not
the easy path.

"Gina Logan's shop is in Brooklyn," said Sherlock, naming the street.

"That's one block from me," Henry said.

"Then we can check on your roommate on the way," said Joan.

Henry consulted his pocket watch. It was understated but elegant, rather like Joan Watson. The timepiece was, of course, considerably older. "Very well. I confess I am curious."

"You'll be an asset," said Sherlock, and Henry saw Joan's stare of total amazement at the compliment. Sherlock blinked at her, expression bland.

There were occasions when the living were as mysterious as the dead, Henry concluded, and followed them out.

Ms Logan was packing a suitcase as they arrived at the small antiques store she had run with her business partner. She was not pleased to have three visitors asking questions.

Henry looked around the shop. There were many fine pieces here, not only grand items such as venerable old clocks and crystal, but also domestic objects that had once belonged in more ordinary households. He exclaimed, finding a pen and inkwell set of the same maker he had once favoured.

"Are you an antiques aficionado, Dr Morgan?" Sherlock asked sharply.

"In a small way," said Henry, turning the pen over in his hands. "This was a very reliable manufacturer, I understand."

Sherlock's eyes were on him, calculating. Henry put down the pen. "Ms Logan," Sherlock said, swinging round abruptly to face the woman. "Where are you going?"

She glared at them all. "My mother's. I'm upset. Obviously."

She did not look in the least upset. She simply looked cross.

"Do you know of a diamond box," Joan asked her. "Your late partner was very keen for you to have it."

"Yes," she said. A shadow passed over her face. "What makes you say he wanted me to have it?"

Sherlock ignored that. "Is it valuable?"

She shrugged. "See for yourself." She plucked it from her open suitcase and held it out on the palm of her hand.

The box was indeed diamond shaped. But it appeared to be plain wood. There was a pattern of inlaid wood on the top, but no hinge or catch.

"That's odd," said Joan. "The will said -"

Sherlock cut across her. "It's a puzzle box, is it not? Do you know the answer to the puzzle?"

"Of course," she said, making to put the box back.

"May I." Sherlock strode across the room, stretching out his hand.

"No - I'd much rather you didn't -"

"What have you got to hide, Ms Logan?" Sherlock asked. "Is it full of treasure?"

"It's sentimental." She held it carefully, stepping back from Sherlock's reach.

"Oh really? A gift from him to you."

"No. I gave it to him." Ms Logan scowled.

"How charming," said Sherlock. "From you to him. Did he like it?"

"He never opened it."

"You seem very certain of that," Henry said. "I suppose he couldn't solve the puzzle." He had a clear view of her suitcase. The contents were those of a person about to disappear for more than a weekend. This was the packing of a woman about to start a new life.

"And so at the last moment your partner thought to make sure you had the gift back. How exceptionally considerate." Sherlock made a grab for the box, and missed.

Gina Logan thrust the box deep into her case, under a bag of toiletries.

"That's it," Henry said. He strode to the case and pulled out the toiletries bag. He located a tube with French writing on it , unscrewed the cap and sniffed. "I knew the texture of the trapped skin was odd."

"The skin under our victim's nails," Joan said.

"Yes," said Henry. He held up the tube. "That skin was greasy with moisturizer. A rather fragrant, feminine moisturizer. Ms Logan, why did you kill your business partner?"

Ms Logan darted for the door but Sherlock caught her by the arm. "He knew you wanted to kill him. didn't he? And I suppose that means you get ownership of everything in this lovely little shop, stuffed as it is with treasures from a bygone age. No more sharing the spoils with your partner. Watson, call the police."

"Wait," Joan said, "what's in the box? If he knew she was going to kill him, why give back the box?" She reached for it.

"No!" Henry thrust himself in her way. "Don't touch it." Joan frowned at this but Henry saw Sherlock give a crooked smile. Odd.

Joan pursed her lips. "Why?"

"Because it's a trap," said Henry.

"Diamond encrusted," said Sherlock. "Phrasing guaranteed to get the police interested. But the box is diamond shaped, not diamond encrusted at all."

"And even if it were," said Henry, "why would you make such a point of stating that it belonged to your would-be murderer?"

Ms Logan wriggled but Sherlock held firm. "Unless," Sherlock said, "you knew it contained something incriminating. Something which would prove she was going to make an attempt on your life."

"A puzzle box," said Joan. She picked it up, ignoring their protests. "But the recipient didn't know how to open it."

"Please be careful," said Henry. "It contains - "

But he was too late. Joan's deft fingers had found the hidden catch, and the box sprang open.

Sherlock wrenched Joan aside, yelling at Henry, "Close it up!" He clapped his hand over Joan's mouth and nose.

Ms Logan was scrambling away, her face a mask of horror.

Henry leapt for the box.

As powder exploded from the lead-lined interior of the box, fogging the antiques shop with fine white cloud, Henry saw Sherlock's face. Sherlock was not alarmed at all. He looked calm and interested, putting a handkerchief over his mouth, his eyes alert and fixed on Henry. You know the ending, Henry thought.

The box was open in Henry's hands. Joan was shrieking and Henry wished he could reassure her. He got a whiff of sour metal as the powder swirled around his face, and then his lungs burst into flaming agony, and then his heart stopped, and then nothing.

"Bracing night for it," said Sherlock, holding out a blanket as Henry crawled, drenched and naked, onto the bitter shore of the East River. The sun was up, but barely, and the wind bit.

Henry coughed, the poison still foul in his mouth, and wrapped himself in the blanket. "How did you know?" he asked. "You wanted me to be the one to open the box. You knew I - wouldn't die, but how?"

Sherlock tilted his head back at the starless sky. "Your watch, your speech, your evident comfort and familiarity with a two hundred year old writing implement. And of course, I am a student of this city and all its peculiar mysteries." He dropped his gaze to Henry. "Of which the mysterious unkillable man is certainly one."

"Ah."

"How many times has it happened?" Sherlock's tone was eager, like a schoolboy discovering buried treasure in the back garden.

"Many times," said Henry. Sherlock indicated a pile of dry clothes on the ground, and gestured impatiently for Henry to dress.

"What is your true birth date?" Sherlock asked as Henry pulled on trousers, shoes, shirt and jacket. "Does it hurt, to die? Have you always been like this? What knowledge you must have acquired! Why do you come back in water each time? How does it work?"

"Ignore him," said a quiet voice behind Henry.

Henry turned, in the act of fastening his collar, and there was Joan Watson. She beckoned them up to the street.

"Are you going to tell anyone," Henry asked. He found her calm gaze fascinating. It seemed as though secrets could fall safe into those eyes and never need to resurface, gasping, into the cruel air.

"No," she said. "And Sherlock is going to respect your privacy and not hound you for answers which are obviously difficult for you." She touched his sleeve. "Your life is your own, however many you have."

She understood. "I am made more of death than life," Henry said.

Joan shook her head. She raised her arm and a cab appeared.

Sherlock held his hand out matter-of-factly and Henry knew without asking that it would contain money. But it was a watch that fell from Sherlock's palm to his own. "I lifted it from you when we went into the antiques shop," said Sherlock. "In case the stories were true. Couldn't bear the idea of something so perfect getting ruined with salt water."

"Thank you," said Henry.

"No," said Sherlock, coming to shake his hand, "thank you. There's little in this world that can truly intrigue me. And you, Dr Morgan, are a very intriguing thing indeed."

"Immortality is surprisingly dull, actually," said Henry. "You always know the ending."

"Hush," said Joan. "Don't think of it in terms of endings. Think of it as so many new beginnings." She held open the cab door for him.

Sherlock leaned in through the window as the driver got ready to move away. "Dr Morgan, now that we know each other, may I-"

"Perhaps," said Henry, thinking about escape, about emigration, about never answering any of this man's endless questions. But then he glanced past Sherlock at Joan, standing steady and kind, and he repeated with a little more sincerity, "Perhaps."

Joan smiled, and drew Sherlock back. Henry wound up the window, and the cab pulled away, into the silvery morning of his latest new beginning.

Author's note: I did hesitate about putting this story in crossovers but to me it forms part of my many elementary works, which do include cameos from a couple of other well known characters. It's easy in AO3 as you can tag a story with both fandoms, which is what I've done. But here it won't get seen over on the crossover board, and I wanted my elementary friends to read it! What I might do is an alternative version and add it to the Forever board, hmmm. -Sef