The American Air Force officer was standing with three other rescuers July 8 when they finally felt a quick strong tug on the line that ran from their gloved hands into the murky pool of water at their feet, a chain all the way through the flooded cave to the chamber where 12 young soccer players and their assistant coach had been trapped for 16 days.
The call "Fish on!" echoed off the stone, alerting rescuers up and down the passage that their treacherous mission was underway.
"That was the code word that somebody was coming up," said the officer, who spoke to The Washington Post with permission from his superiors on the condition that he not be identified, reports Washington Post.
The first boy would emerge from the water in 10 minutes. "Everybody's heart stopped," he said.
It was the moment they had all been waiting for, but that no one had wanted. It meant no new exit would be discovered, or drilled, and that the members of the Wild Boars soccer team, who ranged in age from 11 to 16, and their 25-year-old assistant coach could not leave any other way.
The relentless rains were pumping daily deluges into the tunnels, constantly threatening to overwhelm the battery of borrowed pumps and swamping the boys' tiny refuge as a horrified world looked on.
It meant the air had begun to fail, with oxygen levels falling to near blackout levels. It had all come down to this last, best, terrible option that planners assumed would mean the death of least some of the boys, none of whom could swim. It meant pulling a terrified child through the frigid waters of the cramped, flooded, 2 1/2-mile-long gantlet that had already killed one expert diver.
"You could hear everybody stop breathing," the officer said.
The first boy would make it out, but would he make it out alive?
The unprecedented rescue operation that gripped the world and overwhelmed this mountainous outpost in northern Thailand for three weeks - recounted here based on interviews with more than 30 participants - began June 23 with a flurry of texts messages: A lot of sons were late for dinner.
Nopparat Khanthavong, the 37-year-old coach of the Wild Boars, knew his assistant coach had taken some of the younger players out for a Saturday bike ride while he watched his older team play.
After the final whistle, Nopparat checked his phone and saw at least 20 worried messages from his players' parents asking why the bike riders had not returned. When he learned the children had persuaded his assistant to take them into the six-mile-deep Tham Luang Nang Non cave, he headed that way. The cave was popular, but Nopparat, standing under a darkening sky, knew that the rainy season was no time to be in those endless, flood-prone passages.
He stopped to consider the abandoned bicycles around the entrance and the worsening precipitation rushing down a lushly wooded mountain slope. He raced in, screaming the names of his assistant and the boys.
"I had no flashlight," Nopparat said. "In just a few meters, I couldn't see anything."
But soon he did see lights, coming out from the deeper recesses. It wasn't his team; it was a group of park employees who also had seen the bicycles and gone to investigate.
"If your players are in there, they are trapped," one told him, imploring him to calm down. Several hundred meters down the winding, narrowing passages, they had found water, blocking the way and rising quickly.
When Napasorn Taturkarn's phone rang, the mayor of Baan Moo 9 was with a group of neighbors. They were practicing Thai music for the funerals and weddings she plans for the village of 700 houses less than two miles from the cave's entrance.
It was her friend, Nopparat. "I think my boys are in the cave," he said. "Can you help?"
The first responders to a crisis that would soon captivate millions were the musicians in her yard, Napasorn said. At the cave's entrance, they found Nopparat pacing frantically in the fading light.
"He looked very concerned," Napasorn said.
While Nopparat and the village residents made another trip in, Napasorn called the Siam Ruamjai, the local volunteer emergency squad based in a pink building a few miles down the main road.
"I've been in the cave before," said Niwat Tumploy, 27, who took the call. "But only when it was dry. In the rains, that is a bad place."
Ten volunteers jumped in an ambulance and the back of a pickup. At the cave, five joined the growing crowd at the entrance; five went in, including Niwat. The rain had become a torrent. Water in the passage was up to their ankles even before they reached the watery impasse. Within two hours, it would be nearly to their waist.
"There was nothing we could do," Niwat said. "We needed the big guys."
The governor of Chiang Rai Province, Narongsak Osatanakorn, weeks away from being transferred to another part of the country, was getting ready for bed when he got word of the missing kids. He assumed it was "just some boys in the cave, no big problem," he told The Washington Post.
But after changing from pajamas to drive the 38 miles to the cave, he knew differently. Within hours, the first members of the Thai navy SEAL team arrived and went into the water.
Thai SEALs practice rescues in open water. They were unprepared for dark muddy currents running between sharp rock walls. Feeling their way along the jagged edges, they turned back. A bigger group tried again, but when they reached an intersection in the narrow passage, they were baffled. The cave was a maze, and the water was rising.
"We could not fight with the weather or the water anymore," said Aparkorn Youkongkaew, the Thai navy SEAL commander in charge.
A radio reporter arrived from Mae Sai; word began to spread. By daylight, local people were bringing food, a corps of volunteer cooks that would swell to more than a hundred. A truck arrived with a small industrial pump, which workers carried to the edge of the flood, the right idea at the wrong scale.
"They were pumping, but they were not enough to handle so much water," said Kobchai Boonyaorana, a Thai disaster management official. "The rains were getting harder. We needed more."
The call for pumps went out, and they began to arrive from all over the country. Worawut Imchit drove overnight from a shrimp farm 850 miles to the south, four flatbed trucks carrying four of the massive pumps that circulate water through the ponds.
"It was three sleepless days for me," said Imchit. "I ran like a crazy man, up and down, back and forth between the pumps to make sure everything was functioning normally."
Within three days, more than 40 machines had arrived, Kobchai said. At more than 400,000 gallons an hour, the pumping power stabilized the water level, and lowered it on drier days. Downhill, it flooded the fields of 128 farmers, destroying their rice harvests for the year.
Inside, divers said they worked without any sense of day or time in the all-consuming darkness.
As teams got deeper into the cave, radio links broke. The teams resorted to hand-carried notes, messengers running and swimming the communiques in relays. Commanders lost touch with their men for hours at a time.
Asaf Zmirly, an Israeli living in Bangkok, arrived with radios flown in from Israel that could operate within the cave, adjusting to the topography and creating a daisy-chain-like network. Just the shallow foray he made into the water to establish the system was daunting.
"If you look to your right or the left, the mask will be pulled off your face," Zmirly said.
Even when they could talk to each other, searchers did not know where to look or how to find their way. The SEALs would find themselves essentially lost after hours-long dives, with still no sign of the young boys. On June 27, fast-rising waters filled the cave - so fast that it would be the equivalent of a house flooding in 10 minutes.
"Our three hours of draining became nothing," the Thai navy commander said.
They found help from an unlikely expert.
Vernon Unsworth, a British insurance consultant and hobbyist spelunker, has made an obsession of the Tham Luang cave system. He had explored miles of it over a decade, planning his travels between England and Thailand around the rainy season. He was convinced that the Thais were looking in the wrong place. Unsworth had strong views on where to look and who should be doing the looking.
"Time is running out," he wrote in a letter to the governor, according to Unsworth's wife. He listed the names of three British cave divers he pegged as the best in the world. "Please contact them through UK Embassy ASAP."
The Thai government agreed.
Within days, his Brits were in the cave, and a search that most had given up as futile took an electrifying turn.
On July 2, Rick Stanton, a former firefighter, and John Volanthen, an IT consultant, used Unsworth's maps to reach a chamber more than 2 1/2 miles from the entrance. When their headlamps emerged from the water, they reflected in 13 pairs of eyes that had not seen sunlight in more than 200 hours.
The boys and their coach were alive after nine days of pitch-black isolation, six without any food. Clinging to a slippery slope 15 feet above the current, they had licked water droplets from the limestone walls. Their assistant coach, Ekapol Chanthawong, a former Buddhist novice monk, taught them to meditate to keep them calm.
"How many of you? Thirteen? Brilliant," Volanthen said. He assured them: "Navy SEALs will come tomorrow, with food and doctors and everything."
Instantly, a search had turned into a rescue. Hundreds of volunteers and military personnel clogged the mountain roads to the cave, an ad hoc battalion of experts and adventurers from around the world.
More than 1,500 journalists descended on the small town, racing to feed an insatiable interest in the scrappy teammates, some of whom were stateless migrants from a lawless region of neighboring Myanmar. The boys, assumed lost, now had a fighting chance to make it. Their families, who had been keeping vigil in a muddy encampment outside the cave, were jubilant.
Piyada Chermuen, 16, came from the same village in Myanmar as Adul Sam-on, the English-speaking boy able to communicate with the British divers. They lived in the same Christian church with 20 other refugees, most of whom were sent to Thailand by their parents so they could go to school.
Adul, 14, one of the Wild Boars' best players, speaks five languages.
"We were praying for him when the teacher ran in and said they had been found," Piyada said. Outside her classroom, a string of photos of Adul hung like prayer flags. "Thank God. We cheered so loud."
At the cave, activity exploded. Thai police set up satellite parking areas and shuttled volunteers - who came to number more than 9,000. Commanders established one-way traffic lanes within the cave. Deeper in the chamber, four SEALs kept watch on the boys as their comrades ferried in field rations and water.
Ideas came from every corner: a network of corrugated pipes the boys could crawl through; floating them out in body bags. Billionaire entrepreneur Elon Musk began construction of a custom kid-sized minisub.
But rescuers were focused on three possibilities: diving, drilling and waiting.
Multiple crews scoured the slopes for a spot to bore an access hole. After testing more than 100 sites, only 18 were deemed even remotely viable. And even drilling into the right hole could cause a deadly cave-in.
Waiting out the rains was quickly dismissed by many of the rescuers. Unsworth cautioned them that flooding from northern Thailand's monsoon season can last into winter, raising the possibility that the kids and their guardians would be perched on the cold, dripping slope for five months. Feeding them would require some 2,000 meals. And oxygen was proving to be a critical need just two days in. With more adults in the cave, O2 levels were dipping.
Saman Kunam, a retired Thai navy diver, was working to fix that on the night of July 6. He and his team were staging oxygen tanks along the flooded passage, with tubes to pipe it to the boys' chamber. Navy commanders paced outside the cave's mouth as hours dragged by without word from the team. The divers finally emerged seven hours later, carrying a lifeless body: Saman's own tank had run out.
After officials announced his death at a morning briefing, even some of the boys' families questioned the viability of having their sons dive out. They suggested that waiting for the dry season might be best, Nopparat, the coach, told The Washington Post. The jubilation that erupted after the boys were found drained away.
Prayuth Jetiyanukarn, the robed abbot of the hilltop Buddhist monastery where the assistant coach often slept, penned a short letter to the young man, slipped it in a plastic tube and gave it to a Thai diver who promised to carry it in.
"Be patient. Try to build your encouragement from the inside," it read, according to the abbot. "This energy will give you the power to survive."
Inside the cave, though, were 12 soccer players, still trapped in deteriorating conditions. Preparations for a water exit were building.
Rescuers built a mock-up of the tight passage with chairs. They practiced with local boys of the right size in a school swimming pool, perfecting the muscle memory they would need in the cave, said the U.S. Air Force officer.
Inside the cave, the boys and their coach told their rescuers they were ready to go.
"They were the ones who needed the least convincing," said U.S. Air Force Maj. Charles Hodges, who led the American team and was so new to his new posting that his belongings had not arrived in Okinawa, Japan.
On July 6, the American military and Thai SEALs took a jointly concocted plan to senior Thai government officials. The interior minister was among those who arrived at the cave entrance by motorcade. Using Unsworth's maps and his understanding of the chamber's topography and hydrology, they pressed their point to about 60 representatives from the civilian government: It was time to act, even though they fully believed that some of the boys would not survive the swim. Their message: Save most of them now or lose all of them soon.
"You can wait until that finite window of time is over," Hodges said he told Thai officials, "and I can almost guarantee you that all of them will die."
The Thai interior minister requested that Hodges and about eight others go into a private room. He wanted to hear their plan again. Hodges explained the mission's two parts, emphasizing it would take an entire day of preparation before the first boy would be pulled through the water. The Thais would continue to search for a drilling site if the diving plan failed.
They got their green light.
On July 7 - two weeks to the day since the boys went missing - the rescue plan, while not publicly acknowledged, was underway.
Air tanks were stashed along the muddy passageways, enough for the 12 boys, their coach, the four SEALs who had embedded with them, and the 18 divers who would carry them out. Riggers strung a web of static ropes for hoisting the cocoon-like stretchers over vast fields of jagged rocks.
By 10:30 a.m. on July 8, the core team of 18 divers was in the water: Among them, Brits, Thai SEALs and diving buddies from the Gulf of Thailand beach resort of Koh Tao.
One group made its way to the final chamber. By the time the divers emerged, the players and Coach Ek, as Ekapol was known, had elected the boy who would go first. Officials have refused to identify him, but friends and parents said he was Mongkol Boonpiem, a 13-year old with a lucky name: "the auspicious one."
The wet suit, the smallest they had, still did not cling to his emaciated frame like it should. They readied the mask, attached to a tank filled with 80 percent oxygen. The rich mixture would saturate his tissues, making him easier to revive if he stopped breathing.
Richard Harris, an Australian anesthesiologist and cave diver, gave the boy a final assessment. The boy was given what Thai and American participants described variously as a muscle relaxant or anti-anxiety medication. A panic attack in a chokepoint no bigger than a manhole would almost certainly be fatal.
Finally, the boy was swaddled in a flexible plastic stretcher - akin to a tortilla wrap, Hodges said - to confine his limbs and protect him from the cheese-grater walls. And then, with his teammates watching, they pulled him under the murky water.
The original plan had called for two divers - one in front of the stretcher, one behind. But that configuration was scrapped as too bulky for the shoulder-width passages and elbow turns.
"Having that second person provided you nothing," the U.S. Air Force officer said.
Instead, a diver kept the swaddled boy in a body-to-body clinch for as much of the swim as possible, the officer said, handing the boy over to a fresh diver after his designated stretch. Keeping the child warm was critical.
"Even then the divers would get cold," the Air Force officer said. "That is a lot of time in the water, and water is constantly running in there because of the flow, so that pulls that body heat away even if you have a wet suit."
The worst portion of the swim was the last one, a deep tubular swoop that held the water like a sink trap. All told, it was a grueling two-hour trek through muck-filled passages.
"It is crawling through mud and underwater tunnels, and you can't see your hands," said Erik Brown, a Canadian diver who was among the 18.
But it was the end of the deadliest part.
The divers lifted the boy, and the crew at the edge of the water pulled him out. Their dry, final passage out was lined with more than 100 rescuers. One of them, the U.S. Air Force officer, put his ear to the boy's mask.
He was breathing. And now, the rescuers could, too.
"It was a huge weight off our shoulders," the officer said.
They got three more out that day, four the next and five on the last. They were hard to distinguish with their face masks, apart from Coach Ek, who still had his wolf-shaped ring on a finger. With each repetition, they grew more efficient.
On July 10, a helicopter's lights shone down on the town of Mae Sai, its whir breaking through the night sky. Celebrations erupted - the last boy was alive, on his way to the hospital. Rescuers cracked open beers, hugging and trading high-fives.
Then they caught themselves. Four Thai navy SEALs were still in the deepest chambers, making their way out after volunteering to keep vigil with the boys.
Disaster almost struck.
The pumps had held the water at bay until the last moments, when one of the industrial-sized hoses burst, pouring water back into the cave. The divers who stayed made a run for it.
"Guys started diving down this hill and trying to get out," said the Air Force officer, who was the very last person out of the cave. "It was a little dicey."
In town, drivers honked car horns in the streets. Family members rushed to the eighth floor of the hospital in Chiang Rai, an hour away. There, crowds gathered behind barriers flanking the entrance and cheered every arriving ambulance. Inside, doctors declared the Wild Boars in good health overall, releasing video of them waving from their group ward.
After 21 days together in darkness, they were still side-by-side in the bright fluorescence of a welcoming world.