Updated at 10:25 a.m. ET on June 17, 2019.

1. The Disappearance

At 12:42 a.m. on the quiet, moonlit night of March 8, 2014, a Boeing 777-200ER operated by Malaysia Airlines took off from Kuala Lumpur and turned toward Beijing, climbing to its assigned cruising altitude of 35,000 feet. The designator for Malaysia Airlines is MH. The flight number was 370. Fariq Hamid, the first officer, was flying the airplane. He was 27 years old. This was a training flight for him, the last one; he would soon be fully certified. His trainer was the pilot in command, a man named Zaharie Ahmad Shah, who at 53 was one of the most senior captains at Malaysia Airlines. In Malaysian style, he was known by his first name, Zaharie. He was married and had three adult children. He lived in a gated development. He owned two houses. In his first house he had installed an elaborate Microsoft flight simulator. He flew it frequently, and often posted to online forums about his hobby. In the cockpit, Fariq would have been deferential to him, but Zaharie was not known for being overbearing.

To hear more feature stories, get the Audm iPhone app.

In the cabin were 10 flight attendants, all of them Malaysian. They had 227 passengers to care for, including five children. Most of the passengers were Chinese; of the rest, 38 were Malaysian, and in descending order the others came from Indonesia, Australia, India, France, the United States, Iran, Ukraine, Canada, New Zealand, the Netherlands, Russia, and Taiwan. Up in the cockpit that night, while First Officer Fariq flew the airplane, Captain Zaharie handled the radios. The arrangement was standard. Zaharie’s transmissions were a bit unusual. At 1:01 a.m. he radioed that they had leveled off at 35,000 feet—a superfluous report in radar-surveilled airspace where the norm is to report leaving an altitude, not arriving at one. At 1:08 the flight crossed the Malaysian coastline and set out across the South China Sea in the direction of Vietnam. Zaharie again reported the plane’s level at 35,000 feet.

Eleven minutes later, as the airplane closed in on a waypoint near the start of Vietnamese air-traffic jurisdiction, the controller at Kuala Lumpur Center radioed, “Malaysian three-seven-zero, contact Ho Chi Minh one-two-zero-decimal-nine. Good night.” Zaharie answered, “Good night. Malaysian three-seven-zero.” He did not read back the frequency, as he should have, but otherwise the transmission sounded normal. It was the last the world heard from MH370. The pilots never checked in with Ho Chi Minh or answered any of the subsequent attempts to raise them.

Primary radar relies on simple, raw pings off objects in the sky. Air-traffic-control systems use what is known as secondary radar. It depends on a transponder signal that is transmitted by each airplane and contains richer information—for instance, the airplane’s identity and altitude—than primary radar does. Five seconds after MH370 crossed into Vietnamese airspace, the symbol representing its transponder dropped from the screens of Malaysian air traffic control, and 37 seconds later the entire airplane disappeared from secondary radar. The time was 1:21 a.m., 39 minutes after takeoff. The controller in Kuala Lumpur was dealing with other traffic elsewhere on his screen and simply didn’t notice. When he finally did, he assumed that the airplane was in the hands of Ho Chi Minh, somewhere out beyond his range.

The Vietnamese controllers, meanwhile, saw MH370 cross into their airspace and then disappear from radar. They apparently misunderstood a formal agreement by which Ho Chi Minh was supposed to inform Kuala Lumpur immediately if an airplane that had been handed off was more than five minutes late checking in. They tried repeatedly to contact the aircraft, to no avail. By the time they picked up the phone to inform Kuala Lumpur, 18 minutes had passed since MH370’s disappearance from their radar screens. What ensued was an exercise in confusion and incompetence. Kuala Lumpur’s Aeronautical Rescue Coordination Centre should have been notified within an hour of the disappearance. By 2:30 a.m., it still had not been. Four more hours elapsed before an emergency response was finally begun, at 6:32 a.m.

The mystery surrounding MH370 has been a focus of continued investigation and a source of sometimes feverish public speculation.

At that moment, the airplane should have been landing in Beijing. The search for it was initially concentrated in the South China Sea, between Malaysia and Vietnam. It was an international effort by 34 ships and 28 aircraft from seven different countries. But MH370 was nowhere near there. Within a matter of days, primary-radar records salvaged from air-traffic-control computers, and partially corroborated by secret Malaysian air-force data, revealed that as soon as MH370 disappeared from secondary radar, it turned sharply to the southwest, flew back across the Malay Peninsula, and banked around the island of Penang. From there it flew northwest up the Strait of Malacca and out across the Andaman Sea, where it faded beyond radar range into obscurity. That part of the flight took more than an hour to accomplish and suggested that this was not a standard case of a hijacking. Nor was it like an accident or pilot-suicide scenario that anyone had encountered before. From the start, MH370 was leading investigators in unexplored directions.

The mystery surrounding MH370 has been a focus of continued investigation and a source of sometimes feverish public speculation. The loss devastated families on four continents. The idea that a sophisticated machine, with its modern instruments and redundant communications, could simply vanish seems beyond the realm of possibility. It is hard to permanently delete an email, and living off the grid is nearly unachievable even when the attempt is deliberate. A Boeing 777 is meant to be electronically accessible at all times. The disappearance of the airplane has provoked a host of theories. Many are preposterous. All are given life by the fact that, in this age, commercial airplanes don’t just vanish.

This one did, and more than five years later its precise whereabouts remain unknown. Even so, a great deal about the disappearance of MH370 has come into clearer view, and reconstructing much of what happened that night is possible. The cockpit voice recorder and the flight-data recorder may never be recovered, but what we still need to know is unlikely to come from the black boxes. Instead, it will have to come from Malaysia.

2. The Beachcomber

On the evening of the airplane’s disappearance, a middle-aged American man named Blaine Gibson was sitting in his late mother’s house in Carmel, California, sorting through her affairs in preparation for selling the property. He heard the news about MH370 on CNN.

Gibson, whom I met recently in Kuala Lumpur, is a lawyer by training. He has lived in Seattle for more than 35 years but spends little time there. His father, who died decades ago, was a World War I veteran who endured a mustard-gas attack in the trenches, received a Silver Star for gallantry, and went on to serve as the chief justice of California for more than 24 years. His mother was a graduate of Stanford Law School and an ardent environmentalist.

Gibson was an only child. His mother liked to travel internationally, and she took him with her. At the age of 7 he decided that his life’s goal would be to visit every country in the world at least once. Ultimately this challenged the definitions of visit and country, but he stuck with the mission, forgoing any chance of a sustained career and subsisting on a modest inheritance. By his own account, along the way he dabbled in some famous mysteries—the end of the Mayan civilization in the jungles of Guatemala and Belize, the Tunguska meteor explosion in eastern Siberia, and the location of the Ark of the Covenant in the mountains of Ethiopia. He printed up cards identifying himself: adventurer. explorer. truth seeker. He wore a fedora, like Indiana Jones. When news arrived of MH370’s disappearance, he was predisposed to pay attention.

Despite reflexive denials by Malaysian officials, and outright obfuscation by the Malaysian air force, the truth about the airplane’s strange flight path quickly began to emerge. It turned out that MH370 had continued to link up intermittently with a geostationary Indian Ocean satellite operated by Inmarsat, a commercial vendor in London, for six hours after the airplane disappeared from secondary radar. This meant that the airplane had not suddenly suffered some catastrophic event. During those six hours it is presumed to have remained in high-speed, high-altitude cruising flight. The Inmarsat linkups, some of them known as “handshakes,” were electronic blips: routine connections that amounted to the merest whisper of communication, because the intended contents of the system—passenger entertainment, cockpit texts, automated maintenance reports—had been isolated or switched off. All told, there were seven linkups: two initiated automatically by the airplane, and five others initiated automatically by the Inmarsat ground station.