Up-and-coming country star Luke Combs had just started his set on the smaller of the two festival stages when Kody Robertson, an auto parts salesman from Columbus, Ohio, squeezed in at the end of the bar next to Michelle Vo, an insurance agent from Los Angeles.

The 32-year-olds connected immediately. They joked about their mutual love of golf. He recommended new beers for her to try as she showed him the large floral tattoo covering much of her back. They realized that they were both staying at the Luxor.

A longtime country music fan, Robertson was in Vegas with a group of friends and told Vo about the fun they'd had at last year's Route 91 Harvest festival. Vo replied that she'd only recently fallen for the genre; this was her first festival. She was here alone. By the time the night's final act took the main stage, the fast friends had settled into a spot about 20 yards from the right side of the stage, nestled between a few cuddly married couples and a rambunctious bachelorette party.

Then the first shots were fired.

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It was 10:08 p.m. Robertson and Vo searched the air for the fireworks they assumed they were hearing. Then came a second burst: indiscriminate gunfire hailing from a 32nd-floor window at the Mandalay Bay Resort and Casino.

Screams punctuated the pop-pop- pop. Jason Aldean, the headline act, ran from the stage. A bullet pierced the left side of Vo's chest.

"She got hit and I turned and saw her immediately fall to the ground," Robertson recalls. "She was literally right beside me, maybe two feet away."

Robertson threw his body on top of hers as a shield from the bullets and, when the firing finally seemed to stop, worked with another man to carry Vo out of the venue — pausing for cover each time the gunfire resumed.

Sunday night's massacre in Las Vegas — the deadliest mass shooting in modern American history — left at least 58 people dead and 527 injured. Frantic accounts and shaky videos from the venue replay the pandemonium as thousands of concertgoers began trying to hide and scrambling to escape.

"Michelle, Michelle!" Robertson screamed as he and the other man took turns performing CPR on Vo, who was no longer responsive. "Wake up!"

Finally outside, Robertson spotted a white pickup truck whose driver was headed to a hospital. He set Vo down on the truck bed, then ran back toward the stage.

The promise

Back inside, clusters of bodies lay crumpled along the ground as ammunition dinged the metal roof of the bar near the back of the venue. Robertson saw people hiding behind food stands. Dozens crouched horrified beneath the bleacher seats.

In the heartbeats between bullets, Robertson and other would-be rescuers ran from person to person, checking pulses and pulling bleeding bodies to safety.

"We put a girl on a beer cooler to try to push her out, we were carrying people out on the steel barriers from the perimeter," Robertson said. "Wives screaming at husbands to wake up, and a husband on top of his wife trying to do CPR."

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Then he saw it: Vo's purse, on the ground near where they'd been dancing. Her phone wasn't inside, so he furiously called the number Vo had given him earlier until, finally, someone answered. Another group of concertgoers had found the phone as they ran for the exits. Robertson could pick it up at Planet Hollywood.

By the time he retrieved it, Vo's phone was full of frantic text messages and voice mails, which he couldn't open without her passcode. The consensus of workers at a nearby casino was that Desert Springs was the closest hospital, so Robertson started walking, on the way texting his own family and friends to let them know that he was safe.

It was past 3 a.m. by the time he arrived, and the hospital was locked down. No one was allowed in, and little information was coming out. The blood covering his jeans and arms had begun to dry dark crimson when Vo's phone buzzed.

"Please tell me that she's okay," Jeremiah Hawkins, 37, the husband of Vo's oldest sister, begged through the phone.

Robertson relayed what he knew: She had been shot in the chest and taken to a hospital. He'd keep looking until he found her. He promised.

The search

Robertson had been waiting for more than an hour before the lockdown ended and people were slowly allowed into the hospital. It had been hours since he'd seen Vo and, with her purse still clutched in his arms, he ran up to a police officer just inside the entrance.

Do you have a woman named Michelle? Five-foot-three. Asian. A big flower tattoo on her back. She won't have any ID on her; I have her purse.

The officer checked. Vo wasn't there.

Robertson called all of the other hospitals he could find. None of them had her. He dialed the information line set up by the police, at least 60 times he thinks. Nothing.

[As Las Vegas grieves, investigators struggle to uncover motive behind shooting rampage]

Still pacing in the hallway of Desert Springs, he dialed Hawkins and told him that he still didn't know much. Eventually, the hospital staff told Robertson that he had to leave. He began the four-mile walk to the Luxor.

"Who would shoot into a concert?" he asked himself aloud as he walked. "She was two feet away from me. How lucky am I? It could have been me. It should have been me."

The news

A thousand miles north in Washington state, Hawkins was still working the phones. An endodontist, he figured he could use a process of elimination to find his younger sister-in-law.

There seemed to be two major trauma centers in Las Vegas, and workers at one told him they had already cleared all of their Jane Doe cases. Vo must be at the other.

"I kept being afraid that Kody wouldn't pick up, or Kody would leave, that he would drop us along the way," Hawkins recalls. "I was calling every hospital, and every operating room, and every time I called Kody, he answered. Every message, he responded. Every time we needed him to do something, he did it."

This call reached Robertson about 5 a.m., back at the Luxor where he was still wearing the bloody jeans and flannel shirt from the concert.

"Have you tried Sunrise Hospital?" Hawkins asked.

Robertson pulled off his cowboy boots, put on tennis shoes, and waved down a cab. Minutes later, he was at Sunrise, describing Vo to the worker behind the front desk.

Five-foot-three. Asian. Dark Hair. A big flower tattoo on her back.

She might be here, the hospital worker told Robertson, before pointing him to the auditorium where the families and friends of the unaccounted for were gathered. The room had phone chargers and Krispy Kreme doughnuts and platters of hot meals donated by Denny's. Doctors and counselors and police officers trickled in and out with updates. Someone brought in a comfort dog for those in need of something to hold. Every 20 minutes or so, another family received their news. More often than not, it seemed, the news was not good.

[‘I felt the gunfire would never stop’: A fun-filled concert turned to horror]

As the early morning stretched toward lunch, the once-animated emotions on the faces of the three dozen or so still waiting gave way to sullen stares. Some paced. Others rocked. A few prayed. Robertson ate a doughnut. The coffee went cold.

The news came about 11 a.m. Three women from the hospital — two doctors and a counselor — led Robertson to a small back office.

"Michelle didn't make it," one of the doctors said. "The wounds were too much. She didn't make it."

Robertson called Hawkins, told him he should sit down, and then put the phone on speaker. The doctor said it again.

"She didn't make it."

The counselors talked to Robertson about trauma and about grief. When he tearfully emerged from the front doors, those waiting outside the hospital — a mixture of family members of the wounded as well as local residents — embraced him in a tight hug. A man came up to ask if Robertson was all right. Another came up and prayed with him. For a moment, he felt comfort. Soon it was gone.

"That's when it hit me," Robertson said. "I didn't really want to talk to anyone."

He looked down at his phone, its screen still covered in blood. Four and a half miles to the Luxor. Robertson started walking.

The meeting

He was supposed to depart Monday, but Robertson is still in Las Vegas.

His boss in Ohio told him to take all the time he needs. Southwest Airlines let him change to a later flight. The Luxor extended the stay on his room.

The hotel also extended Vo's room so that her family members would have time to retrieve her belongings. They landed Monday afternoon — a sister, a brother-in-law, some friends — and quickly made their way to the south tower, room 11375, where Robertson was staying.

"Kody was our guardian angel," said Diane Hawkins, 40, Vo's oldest sister, who believes that had Robertson not tracked down her sister, their family would still be searching for her. "He refused to let her be alone."

They thanked him for his help, and his commitment. They talked about Vo's energy, and her joy. When it was his turn, Robertson told one of his only stories from what had been a day-long friendship — how Vo had pulled out her phone to show him pictures of both of her sisters, showing off their beauty in their wedding dresses. Everyone laughed, for what felt like the first time in forever.

And then, together, they all went to check Michelle Vo out of her hotel room.