He soon developed a crush.

On their first date, they drove to Laguna Beach, Calif., visited Sherman Gardens, attended several A.A. meetings, sang karaoke and fed the homeless at a local church. (The date lasted a weekend.) Soon they were living together in a small brown home perched amid the hills in Bodfish, Calif., with fruit trees out back, canning supplies in the kitchen, and an enviable view from the front porch.

Mr. Mason was a cancer survivor and certified nursing assistant who enjoyed target shooting but refused to hit anything living — including trees — and Ms. Harris was an addiction treatment coordinator who had spent years working through her own chronic post-traumatic stress disorder.

Both had been sober for years. They were an obvious match. And country music, with its mix of compassion and grit, was an obvious soundtrack for the relationship.

“She’s just a real strong woman in recovery,” Mr. Mason said, “and I find that to be appealing.”

They were already engaged when they went to Las Vegas last year, pulling on their boots to watch the country star Jason Aldean sing into the night.

When the shooting broke out, a bullet struck Mr. Mason in the foot. Ms. Harris ran to their truck; Mr. Mason threw off his boot, tied a sock around the wound, and then both of them tried to shuttle as many people as possible to safety.

Once they returned to Bodfish, the wound healed quickly. The emotional part has been harder.

“Nightmares, panic attacks, it was pretty intense,” Mr. Mason said. “Now when I hear sounds it’s an automatic instinct, I need to run and hide. I don’t like that. I’m a big old dude. I’m not afraid of things. I own guns. And I haven’t been able to get to a point where I can go and fire my guns off — and I don’t know when I’ll get there.”