Disclaimer : None of this belongs to me but to ACD, Steven Moffat and Mark Gatiss.
Author's note : "Happy birthday EE !"
The case had started in one of the usual ways. A text from an out-of-his depth Lestrade, followed by the Detective Inspector bringing Sherlock some files to review. Really, if he hadn't been so very bored, he wouldn't even have bothered. But, as luck would have it, it'd been nearly a week since the last case and the gnawing feeling in his chest was getting harder and harder to control.
"So, what do you make of it ?" Lestrade asked, pointing at Molly's report.
"It's obvious, isn't it ? Cause of death is oxygen deprivation. Based on the lack of marks around his neck or face, the glaring fact that the body has spent quite some time in warm salt water, and the flora and fauna samples Molly recovered from the skin, first conclusion is the man was killed while scuba diving somewhere in the Carribean, when someone or something must have interfered with his oxygen supply. Now, was that on purpose, or by accident ? The fact that his body was found in a bathtub, at his home, means the body was moved, but not necessarily by the killer. Looking at pictures of his flat, it's easy to tell the man was a thief, and a successful one at that."
Ignoring John's sputtered : "What ?!", Sherlock drew in a breath and delivered the end of his speech.
"That was the easy part. More puzzling is the reason his body was moved, given his death was accidental. And why here, if the man died in the Carribean... Three gemstones were stolen from the Hayward Gallery last week, where they not, Detective Inspector ?"
Lestrade nodded in confirmation, remembering the particulars of that case :
"The gemstones were stolen during the night, and the thief left a very odd signing card in the display box. A skull and a crossbone. Fake, although very good imitations."
"Exactly. The papers wrongly concluded that pirates were involved, some even linking the crime to the most recent release in the "Pirates of the Carribean" movie franchise. I remember John trying to get me to take the case, but I was busy with solving the Red Rose Mystery at the time. Before you get any ideas, John, let me state that I only read your blog when tediously bored, as I was these past few days."
"But what about that murder case ? Why do you think they're linked ?"
"Who would have taken the trouble to bring back a body from the Carribean, especially if the death was accidental ? He didn't die in the Carribean at all."
"But you just said..."
"I said "first conclusion is", not "correct conclusion is". Do try to keep up, Lestrade, it'll save everyone's time, most especially mine. So if the man wasn't killed in the Carribean, but somewhere that looked like the Carribean, where must we look ? Exactly ! An aquarium's scuba diving tank. Nearest one to the Hayward Gallery is Sea Life Aquarium, on the South Bank. Famous for "Snorkelling with Sharks", which allows you to swim with the sharks in a reconstructed reef. Now, I bet that if you check, you'll find one of those garish treasure chests at the bottom of the tank, and that it'll contain the three stolen gemstones."
John and Lestrade exchanged a slightly stunned glance, trying to absorb everything Sherlock had just spouted at them.
"But how did the man die ? And who moved his body ?" finally asked John.
"Ah, now, we're talking ! These files don't contain enough data for me to come to a proper conclusion. A trip to the Aquarium will be necessary. Come, we must get there before it closes !"
For years to come, John would wonder who was the most surprised that night. Was it Sherlock, upon entering the reef and finding everyone dressed like a pirate and in a party mood ? Was it Lestrade that one of the world's brightest minds had not only managed to forget his own birthday but actually looked slightly touched by their gesture ? Was it Molly that Sherlock could sound and act so much like a real pirate, and even managed to pay her a compliment on faking those reports ? Or was it himself, that his carefully hashed plan went undetected by the world's only consulting detective and turned out so beautifully ?