The deaths began slowly. Or, rather, the dying itself was quick: bodies dropping onto polished marble, red soaking starched linen, the thudding noises summoning household staff. The limbs were contorted into agonized poses and the mouths gave off a smell, the staff would tell police and reporters, one that they faltered to adequately describe: it was like rubbing alcohol heated on the stove or white gardenias left to rot in an untended room. It was that smell, a smell with no name—or too many names—that some would cite when trying to explain why they’d huddled in fear in the doorways or down the hall during their employers’ last seconds. But there were also the housemaids who wept as they talked of cradling the heads of the dying, pulling a Frette pillowcase over their own mouths as they frantically dialed for help.

The investigations began as they would have, extra detectives assigned to untangle the threads of endowments, stocks, bonds, illegitimate children with unsupported inheritance claims,  former partners with lawsuits dangling, activists and stalkers rounding out the edges of crowded whiteboards at headquarters. Alibis were offered and confirmed, one detective using a No. 2 pencil to mark off each name as he cleared it from the list and flicked open a new page. Nannies and gardeners and house cleaners were questioned, sometimes over and over; white gloves dusted every bottle of Roundup in the garage and every leather cleaner in the stables, of course finding a thicket of fingerprints that proved nothing at all. None of those chemicals were found at the autopsies anyway, and by the time the bodies had been rolled onto steel tables at the coroner’s offices nobody could detect the odor, duly noted in the reports, always identified by the employees who found the bodies, but varying widely as the cases began to dot the map: floor polish, lighter fluid, rancid sweat. The smell would sometimes return weeks later as housekeepers emptied desk drawers or shook out heavy curtains, sending them rushing to the safety of their employers’ brick-lined patios to gasp in the summer air.

That the bodies were dead was plainly obvious, but there was nothing in the prying open of brains or hearts or stomachs, nothing in the meticulous sampling of blood and hair and tissue, nothing in the second or third reports commissioned by grieving families, that could explain how they had got that way.

What emerged slowly were enough deaths to discern a pattern, from Newport Beach to East Hampton to Breckenridge, reporters camped in front of stone lions announcing yet another death, this one old and infirm, that one young and known for tennis every morning on the back lawn, another for scaling K-2 the year before, live-tweeting the journey while a team of Sherpas carried her bags. After all, people die all the time, and it took some time before the accumulation of a critical mass of causes marked in coroners’ reports as idiopathic or in detective reports as unknown.

It didn’t help that so much else was inexplicable. In one family, the patriarch was found floating in his swimming pool but his wife and children were untouched; in another, the seven senior members of the family board of directors were all found dead at precisely 10 p.m. on a Friday, scattered across four time zones and as many continents. A plane pulled into Kuala Lumpur to find the youngest daughter unresponsive, only minutes after she’d been served her second sloe gin fizz. This time what emitted from her mouth, even as the muscles began to stiffen, was an odor of burnt leather and, even more oddly, crushed lemongrass. The youngest daughter’s heirs began to fight over her portion of the empire, a line of shoes and handbags undergoing a rough patch when rumors of Malaysian child labor kept dogging her Instagram feed. It never occurred to them that they might be next.

It wasn’t until five months after the first death—the CEO of a corn and soybean processing giant collapsing in his dressing gown, the smell of sulfur dioxide escaping through the dining room window and alerting his gardeners outside—that anyone realized that’s what it had been. It took two reporters, one from Forbes and another from Corporate Watch (rated “far left/left-leaning” by two nonpartisan media rating sites) to independently reach a sober conclusion.

While the deceased had a remarkable amount in common, hailing from schools with names like Dartmouth and Dalton and tending to belong to the same few clubs, there was one single thread running through every unexplained death, like a string dangling from a pulled tooth. The Forbes editor told his reporter in no uncertain terms to kill the story, but after ending the call he gripped his phone, scrolling through the contacts, a list that had grown three shorter over the previous seven months. He began a text that would serve as a warning, but what would it say?

The day after that conversation, the Corporate Watch web site laid out its observations in simple, unimpeachable graphic form: while many of the country’s wealthiest people were still very much alive, every one of the eleven bodies had appeared on a list of the Fortune 500, and in fact, a chronology of the deaths, though it skipped some entries, leapfrogged its way up the list in perfectly ascending order. Its blogger had chosen that for his title, a warning to those who remained: “The Fortune 489.”

Homicide departments called emergency meetings, reassembled their teams along with FBI agents, dark-suited and flown-in on red-eyes. Nannies and cooks and assistants were resummoned for questioning, detectives picking apart their alibis with renewed vigor. An internal email was leaked—each of its authors insisted that they’d been the victim of hacking —between head actuaries at the country’s top three life insurance companies, proposing that policies be null and void for anyone on the Fortune list; one suggested, “out of an abundance of caution,” expanding it for the country’s top one percent of wealth holders. That furor was eclipsed the following day, when two deaths were reported within hours of each other, in still-ascending order on what several copy editors dubbed the Fortune 487. The Corporate Watch blogger recruited three friends as bodyguards after #thebloggerdidit began trending, the bulk of the comments arguing that his piece had been a public hit list for an assassin nobody could name.

The nation’s top security and risk management company hired 84 new employees in a single day, half of them merely to field the calls and emails that began flooding in two minutes after the piece went live (the company’s online help chat bots were swiftly removed). After reading endless copies of inquest testimony and detective reports and the articles that clogged Twitter with dizzying speed, the CEO of the largest company had to call back a prospective client who’d left three increasingly desperate messages on his personal phone. “So you’re telling me you refuse to protect me?” she snapped before his opening sentence was out. His chair creaked as he sat up with a jerk: “Ma’am, what I’m saying is I can’t protect you. I can charge you to feel protected, and you may decide that that’s worth it to you. But there’s not one thing in common between all of these crime scenes. Not even a common cause of death.” Except no cause at all, he scrawled on a notepad beside him. Except a mysterious smell that could not be replicated and that was never described the same way twice.

One terrified man gave away every bit of his fortune and sold every piece of real estate he had, down to the last stick of furniture. When the voice mails and then certified letters and finally angry tweets begged him to keep it in the family, he closed his account and scrawled, “return to sender” in furious green at the bottom of each envelope. The movers found him collapsed in the foyer of his first home, already plucked and stripped of all his possessions, the sunlight bouncing off empty floors and his body giving off the odor of burning graphite.

The magnate’s lawyers spent months disbursing and reimbursing the funds he’d shed and the stocks he’d unloaded. He’d begun his fortune in agribusiness, but he was particularly fond of his factories making school supplies. There had been an especially ugly case early in his career: two workers had been killed by one of the machines, which had overheated and scalded their faces with steam. He’d been seen weeping at their funerals, and on his death, his family learned that he’d been quietly sending an annuity to the children and grandchildren of both the dead workers. His older daughter cut it off.

His three children staked out what would emerge as the response patterns of the wealthy, even as the deaths began rolling in faster and forming new lists entirely, expanding to England, Mexico, Hong Kong, Dubai. His youngest followed in her father’s recent footsteps, selling off nearly everything (she kept a single silver pendant and one matching watch), sloughing off the stocks and trust payments as fast as they rolled in, holed up in a three-bedroom condo she told herself was safe enough. Her brother’s Instagram feed filled up with snaps of him at Lake Como, on Bali, precisely the same wide grin in every shot. Both of them were still alive six months later, along with the older daughter, who’d taken the reins of the company and hired a firm to fight off a union that had been sniffing around one of the pencil factories.

It was these inconsistencies, and the glaring gaps and inexplicable branching of the lists, that kept earning phrases like capricious twist of fate in news articles, and that spawned multiple watch sites—including one that actually took real bets on who would be next—until it went dark one day without warning. An anonymous collective of hackers and Internet sleuths published the real names of the bettors, which took up the better part of the news cycle until the collapse of the world’s third-wealthiest man. He’d collapsed inside his foyer, surrounded by seventeen armed guards and two assistants and the taster he’d hired for every single dish. One award-winning columnist for Der Spiegel noted that the deaths had reached twenty-nine, every one of them unsolved, and sent out a Tweet: “If God’s not a Marxist, he certainly seems to have done the reading.”

The third-wealthiest man had included in his empire several internationally recognized newspapers; a columnist for one of them, usually on the Fashion and Lifestyle beat, proposed that instead of joining the coverage of the utter chaos at insurance companies and stock advising firms, the estate and tax attorneys booking ninety-hour weeks, the advisors for security and risk management firms quitting in impotent fear, the proliferation of “Really Rich Dead People” trading cards, the conferences of experts poring again and again over autopsy reports, the exhumations of bodies that had long since begun to stink, the utterly indescribable tone of voice from the CEO of the world’s largest venture capital firm on their earnings call a week after the death of three of its five principals, that she seek out the very first household employees, who’d found the very first body, what one macabre headline had dubbed “Billionaire Zero.”

None of them had ever actually met him, the gardeners explained, perched on rickety metal chairs at a Starbucks where customers kept craning their necks at the faces that looked faintly familiar but that they couldn’t quite place. The columnist had only been able to round up two of the four gardeners who’d been working outside that dining room window, shaping hydrangea bushes in the April sun, and one did most of the talking.

Andrés had been in the United States for thirty years; his family had left El Salvador when a neighbor recognized his father Andrés Sr.’s distinctive tattoos, marking him as a commander in a squad that had killed untold civilians at the massacre of El Mozote. He hadn’t known his father’s history until he was much older, Andrés Jr. explained, twisting a slim silver cross around and around in his hands, a present from his father at First Communion.

“I mean, it’s just … it’s so hard to reconcile that with the man who taught me to ride a bike and bragged to all the neighbors when I graduated high school with honors. Imagine learning that you’d lived for so long with someone who brought on that much suffering? The house you lived in, the food you ate, that they came from someone who was carrying all that around inside.” The cross dangled from his fingers and gleamed in the waning light. “That so much death had been walking beside you all along.”