This started out as a plotbunny, trying to figure out how to plausibly unite another pair of brilliant minds (in much the same way as The Detective and the Diplomat), except in this case the gulf is almost 70 years, and I didn't want to use time travel (which has been done to death). This might be a one-shot, or I might continue it into a full story, depending on how it goes. Enjoy! (Disclaimers at the bottom.)
Sherlock Holmes had finally decided that he was starting to get used to retirement. To be sure, the attack of wanderlust he'd suffered at age 65 had taken him from his bees in Sussex to a small railroad town in Nevada called Las Vegas, but he'd managed to find a comfortable level of solitude in a small boarding house there, despite a recent boom in population after the Hoover Dam was completed.
His current landlord, a fiftyish man named Mr. James Carruthers, seemed to respect his need for peace and meditation. As Holmes' own request, he'd furnished a sitting room just as it had been at Holmes' old rooms at Baker Street, and offered him a selection of books to read during his twilight years. Other than that, he was left alone for the most part, and although he was occasionally aware of people coming and going from time to time, he was largely left to his own devices. That was exactly the way he liked it.
He was awakened from a light doze by the sound of arguing downstairs. Oh, bother. He unfolded himself from the wing-backed chair in his sitting room and made his way down the hall to the stairs. He was halfway down to the ground floor when the arguing cut off with a loudpop that sounded disconcertingly like the retort of a firearm. Alarmed, Holmes finished the stairs two at a time and, following the noise to where he'd heard it (for by now he knew every inch of the place like the back of his hand), entered the kitchen at nearly the same time as Carruthers' assistant, Daniel Myerson. The young man was staring in shock at the body of his master, who was lying on the floor in a pool of his own blood. Such was his shock, in fact, that he didn't even notice Holmes standing there, and ran to get help without a word to the retired detective.
This left Holmes alone with the body. He paced round it, and then crouched to examine the gory wound at the back of the skull. Curious, he thought to himself as he found the corresponding entry wound under the left cheekbone. Such a small bullet shouldn't have gone right through, let alone penetrated the back of the skull with such force. What was clear, though, without further examination, was that Mr. Carruthers was the victim of foul play. The weapon was nowhere in evidence at the scene, most likely having been taken with the scoundrel when he left.
Some time later, he was still meditating over the tableau when there was a knock at the front door. Likely the police. Holmes prepared to present his few findings to the officer in charge, to save them the trouble of reexamining the body. He straightened up as a solidly built man in his late thirties or early forties entered. He had a tidily trimmed beard that little more than outlined his round, almost youthful features, so that but for the beginnings of grey in his hair Holmes might have supposed he was younger. In his right hand he carried a curious white box, and he wore a black vest of sorts that read CRIME SCENE in blocky white letters across the chest. This was all turning quite strange…
Myerson joined the newcomer in the doorway, still looking a bit pale.
"How long ago did you find him?" asked the newcomer.
"About an hour ago. I heard the shot and came running, and…" He gestured helplessly. "It's just awful, Mr. Grissom… I mean, this is the first steady job I've been able to find since college…" Myerson looked on the verge of tears, and Mr. Grissom (for so his name seemed to be, gently guided him out.
"We'll do everything we can to find out what happened," Holmes heard Grissom saying in the other room, "Warrick, have Mr. Myerson take you around to see if anything is missing. Greg, Sara, go see if you can find anything in Mr. Carruthers' office that might point to motive."
Holmes tilted his head in interest. Clearly, here was a police officer who valued efficient detection. He stepped forward to speak with the man.
"Catherine, you and I will take the kitchen."
Catherine? Holmes was shocked – this man, whom he had thought was on a parallel with Holmes himself, was not only allowing but instructing a woman to enter the kitchen and see the bloody body? No – this would not do!
He put up his hands to gently block Catherine from entering the bloody scene. He got a bare glimpse of strawberry blonde hair before she entered the kitchen anyway – walking straight through him as if he were not even there. He spun to face her in time to see her stop and give a convulsive shudder.
"What is it?" Grissom asked, now behind Holmes.
"There's an ice cold patch, right by the door," Catherine replied, "Felt like someone walked over my grave when I hit it."
"Well, that's not entirely surprising," Grissom said, and this time Holmes was able to sidestep before he, too, entered, "According to the sign out front, this place is supposed to be haunted."
Catherine turned to face Grissom. "Haunted, huh? Who by?"
Grissom smirked. "The ghost of Sherlock Holmes."
Disclaimer: Sherlock Holmes is the property of Arthur Conan Doyle and Jean Conan Doyle. CSI: Crime Scene Investigation and all related characters are the property of CBS. Don't sue me. I have no money,