The rights to Rex Milligan belong to the late Anthony Buckeridge. Those to Harry Potter belong to J.K. Rowling. Those to the Dana girls, Nancy Drew, the Hardy Boys and others to the Stratemeyer Syndicate. Death in Paradise and Doctor Who are owned by the BBC. Other rights belong to Marvel Comics, DC Comics/Warner Brothers/Hanna-Barbera, Edward Kitsis and Adam Horowitz, the BBC, Jim Butcher, Chelsea Cain, Joss Whedon, Terrance Dicks, the estates of the late Enid Blyton, the late Charles Addams, the late J the late Malcolm Saville, the late Ian Fleming, the late Peter O'Donnell, the late Gerry and Sylvia Anderson and more. I own nothing and make claim to the same nothing.

Early May 2018, Saint Marie, Lesser Antilles

A short plump bespectacled man in a garish full suit strode down the backstreets of Honoré. It was early in the morning. The streets of the Saint Marie capital were largely empty. Other than the odd bemused look that the locals would show anyone in such thick attire in the Caribbean, he was largely being ignored.

The man seemed to be in a hurry. He turned into a back alley. Shots were heard.

Officer Dwayne Myers of the Saint Marie police force was passing by. He ran in but could only see a short plump bespectacled man lying on the ground. This man seemed to have been reaching for his jacket pocket and was muttering something under his breath. Dwayne knelt beside him. "I'll send for an ambulance. Who did this to you?"

"…The golden porpoise! The golden porpoise!" The man muttered and lay still. Dwayne dialled for the Saint Marie ambulance on his mobile but could tell that the man was already beyond medical aid. He rang Detective Sergeant Florence Cassell as well. Dwayne then checked the pocket the man was reaching for when he died. All he found was a ten-inch long hawthorn stick.

"What can you tell us, Dwayne?" asked Detective Inspector Jack Mooney, his usually cheerful Irish accent noticeably muted.

"This is a weird one, chief. I thought I saw a car disappear in the distance. Drive-by shootings are rare here, but not unheard of. But…"

"But what?" Jack prompted. "Anything you can recall might be vital to cracking the case, Dwayne."

"It was just the way he said something. The golden porpoise. That was it. I can't think of anything on Saint Marie called that, chief. A visiting boat, maybe?

"Then he seemed to be have been reaching for something in a jacket pocket. I wondered if it might be for a weapon of some sort. The only thing I could find in that pocket was this." He held up an evidence bag containing the stick. "I don't think that could be classed as a weapon. You could poke someone in the eye with it, chief, but that would be about the worst it could be used for."

"Sure, Dwayne. I agree that this is no weapon from what I can see. As for that phrase, we'll have to research it thoroughly.

"Florence, was anything else found on the deceased? Do we have an ID?"

"Only a British passport in the name of Stuart Johnstone, sir," spoke up DS Florence Cassell in her distinct French accent. "That and a wallet with some East Caribbean and British notes and coins in it, plus some gold and silver coins marked as "galleons" and "sickles" respectively. As far as I can tell from an internet search, these belong to no known currency.

"Stuart Johnstone has no known criminal record and usually works in imports and exports. He had not visited Saint Marie before and only arrived here yesterday.

"One other thing, sir. There was a message from London to say something they called the DQC were informed."

"The Department of Queer Complaints?! That is where we send people alleging family members have been abducted by aliens or their house has a particularly violent poltergeist. Unless he had spoken to the Yard about the Illuminati being after him, why would they need to be informed?

"JP, have you found anything concerning recent gangland activity in that area? We need to know if this is likely to be just a robbery gone wrong?"

"Nothing, chief," replied Officer JP Hooper, the youngest member of the team. "There have been no incidents in that neighbourhood recently. I could have a look around for you…"

"Thanks, JP." Jack sighed. "This whole thing just doesn't make sense. What is this golden porpoise? What was Mr Johnstone doing in that part of Saint Marie? Why would he appear to be reaching for that stick when he was killed? And what in God's name attracted the attention of the Department for Queer Complaints? Answer those questions and we should unearth what was going on."

Florence attached a photograph of the deceased to a white board. "Then we must investigate further, sir. I'll get onto researching what this golden porpoise could be."

The Department for Queer Complaints had been alerted when the Metropolitan Police's computers identified keywords stick, sickles and galleons. From there, it was forwarded to the Auror Department of the Ministry of Magic.

Once Stuart Johnstone was identified as a wizard, the relevant offices were informed of a British mage murdered overseas. A copy of an e-mail to the Metropolitan Police was sent to pulse-hardened tablets and laptops. This gave details of the shooting and Mr Johnstone's strange final words.

"This is a bad business, Harry," Kingsley Shacklebolt muttered to his Head Auror. "We have no idea why Stuart Johnstone was even in Saint-Marie, let alone why anyone would murder him. Neither do we have any notion what this golden porpoise might be. He was an importer of potions ingredients, but we can't think of anything he might be looking for in Saint-Marie."

"He was murdered in a muggle method, Kingsley," Harry Potter noted, "on an island with very few mages. Could it be simply a muggle crime with a wizard victim? Wizards have been in the wrong place at the wrong time and been killed without anyone finding out about magic.

"That said, we do need to look into the matter. Ron and Hermione could go to liaise with the local authorities to see if the Ministry needs to get involved. Both can pose as muggles long enough to not reveal the magical world unless they must. Plus, I think I might be able to get them some off the books help."

"Wonder Witch and her Furies?" Kingsley asked, referring to the wizard world's team of metahuman witches. "I don't think that we need to go into overkill just yet, Harry!"

"I was thinking," Harry told the Minister of Magic with a wry grin, "of an investigative journalist and a pair of detectives. Rex and Louise are on honeymoon in that area and they have Jean with them. Looking into a mysterious death and a strange phrase should be second nature to them."

The Balaska II, The Caribbean Sea

Rex Milligan was lounging by the small swimming pool on the Balaska II's main deck in red swimming trunks, his new wife Louise Milligan nee Dana snuggled into his arms in a red bikini. Louise's younger sister Jean was doing a few laps of the pool in a cream bikini.

The Balaska II was quite the wedding present from the UK and US governments for the assistance Rex and Louise had given over their enhanced lifespans, thanks to Sherlock Holmes' Royal Jelly Honey elixir vitae. Named after Louise and Jean's late Uncle Ned's passenger liner the Balaska, it was a mid-sized yacht with some special features installed by MI6's Q-Branch. For the moment, however, none of the three-person crew were thinking of anything other than enjoying the newlywed's honeymoon.

Discrete red lights started flashing in the doorway to the bridge. Jean quickly climbed out of the pool and dried herself off and the trio put on bathrobes. They then entered the bridge and Rex flicked a switch under the control desk for steering. Three concealed control panels emerged. Jean activated the secure communications array that was controlled from one of these. A panel slid back to reveal a monitor screen on which Harry Potter's face appeared.

"Hi Rex, Louise, Jean! How is the honeymoon going?"

"Very well, thank you, Harry.

"Now, I've known you long enough. You wouldn't use an encrypted secure line for a social call. Let me guess. Something has come up in the Caribbean and you need us to investigate."

"Right, Rex!" Harry explained what he knew of the murder. "I'm sending Ron over with Hermione to liaise with the Saint Marie police. They can provide support to Saint Marie police. In the meantime, please can you three arrange to dock at Honoré harbour for a few days and identify what Mr Johnstone was up to and what this golden porpoise might be."

Jean chuckled. "What is it with us visiting the Caribbean in connection with clues to coloured marine mammals, Sis? Remember that Silver Dolphin case?"

"A white dolphin leading to the deeds of an island shaped like the constellation Delphinus? Treasure hunts have been our metier, Jean.

"Are there any magical species of porpoise, Harry?"

"None that I know of, Louise. There is someone who would. I'll speak to Luna. That's her field."

"Thanks, Harry," Rex concluded. "It's off to Saint Marie, girls. Speak to you soon, Harry."

"You wanted to see us, Commissioner?" Jack Mooney asked Commissioner Selwyn Patterson. "Did I hear something about the Met sending us a couple of consultants?"

"Exactly, Inspector." As always, the Commissioner's voice was slow and serious. "A Detective Chief Inspector Ronald Weasley and his wife, Mrs Hermione Weasley of the Foreign Office.

"Now, I expect you and your team to extend them every courtesy. We need to show that Saint Marie takes the security of foreign visitors seriously."

"You can count on us, Commissioner."

That was true, the Commissioner thought. Like his English predecessors on secondment from New Scotland Yard, DI Humphrey Goodman and before him the late DI Richard Poole, the Irishman hid a keen analytical mind behind an eccentric façade. Whilst he was neither the stereotypical Englishman abroad DI Poole was nor as endearingly clumsy as DI Goodman, DI Mooney had a whimsical manner and a definite touch of the blarney about him. Still, like his predecessors, Jack Mooney's results spoke for themselves. Many a murderer had underestimated the man's mix of tenacity and deductive insight to their detriment. The Commissioner suspected that these Weasleys would be impressed once they got to see for themselves DI Mooney and his team.

Both DS Cassell, barely out of her twenties, and Officer Hooper, still in his mid-twenties, were bright young things, of whom much was expected. The veteran Officer Myers could be lazy and was close to far too many of the island's more dubious characters for Commissioner Patterson's liking (although he would not deny that the underworld contacts had often proved useful in the past), but his new girlfriend Darlene Curtis seemed to be a good influence. Also, Officer Myers generally didn't let the team down in a crisis.

A good team, then. If anyone could unearth what lay behind this baffling case, it was the Saint Marie police force.

The Balaska II moored at Honoré marina. The trio disembarked and ventured into the Saint Marie capital. Seeing a bar open, they sat down and ordered drinks.

"Nice place," Jean commented. "What do we know about Saint Marie, Rex?"

"Saint Marie is an island between Guadeloupe and Martinique, about a tenth of the size of the former. It is a British Overseas Territory but was a French one as recently as the 1970s. About a third of the population are French citizens and French is widely used. Traffic drives on the left, as it does in the UK, but the car number plates are in the French format. The East Caribbean Dollar is the official currency, the main industries are tourism, fishing and sugar production and the principle religions are Christianity, usually Roman Catholic, and various forms of voodoo.

"Saint Marie has a university, an observatory, a newspaper called The Saint Marie Times and about a hundred public beaches. The capital Honoré has a market, bars, restaurants, hotels and the police station, as well as the leisure/commercial marina we are moored at. Nearby is the town of Port Royal.

"One other thing. The island is rumoured to suffer from murder magnetism…"

"What the heck is murder magnetism?!" Louise demanded.

"It is a thesis concerning places with unexpectedly high levels of homicides. You should see the English county of Midsomer's record for that…"

Jean chuckled. "I wonder if there are magnetisms for kidnappings, art and jewel thefts and the like? If so, that would explain Oak Falls and Penfield!" She was referring to her and Louise's home town and the one where their old boarding school Starhurst School for Girls were located respectively. "As for Bayport, Rocky Beach, Sleepyside-on-Hudson and River Heights…"

"I've heard George say the same thing about Kirrin Cottage and Kirrin Island," Rex added dryly. "Jon has added that the Gay Dolphin Hotel, Witchend and Seven Gates seemed to have the same problem.

"In any event, this island seems to have had an unusually high level of homicides ever since the late Detective Inspector Poole was sent here a few years back. Ironically, he was murdered here on Saint Marie himself in the end. It hasn't ended under his successors, first DI Goodman and now DI Mooney."

"So, this is where we spend part of our honeymoon?" Louise sighed. "Only us…"

"Excuse me," said the tall elegant Franco-Caribbean woman who brought the drinks, "but I overheard you mention the murder rate. We have had a number over the last few years, but we have had a near 100% conviction rate for those crimes. My daughter Camille was a Detective Sergeant under Richard Poole and Humphrey Goodman. Humphrey and Jack Mooney are personal friends of mine.

"Now, I, Catherine Bordey, am both the owner of this bar and the Mayor here. Please don't spread rumours and upset your fellow tourists. We do take your security and theirs very seriously."

"We won't," Rex assured her. "Trust me, we don't want Saint Marie to lose its income from tourism."

Catherine nodded. She did, however, make a mental note to speak to Jack and Florence about these strange new tourists. After all, Saint Marie had a history of strange tourists being either murderers or their victims…