When Louis Cardin signed up for the Marines' delayed entry program, he still had a year to go at Temecula's Chaparral High School.
Cardin -- a tall, blonde guy with a ready grin in photographs -- was already seeking something bigger.
The next spring, he graduated from high school on a Friday. On the following Monday at 5 a.m., Marines arrived to collect him for boot camp in San Diego.
"It was the challenge," his mother, Pat Cardin, said in a recent interview about her son.
"Kids don't really know what they want at that point in high school. Some kids are brilliant enough to say, 'This will give me an opportunity to think about what I want to do. At the same time, I've got a challenge going.'"
Louis Cardin served in the Marine Corps for a decade.
There was a 2007 deployment to Iraq at the height of the war and three to Afghanistan -- a tough way to spend one's late teens and early 20s.
Pat Cardin said her son never consciously planned to make the Marines a lifetime career. But he re-enlisted while on one deployment, and then again after he made staff sergeant, a rank that put him in a leadership role among his troops.
The re-enlistment bonus was a factor, his mother remembers with a chuckle.
A single guy with no children, Louis liked nice things. His 2014 Chevy Impala with leather seats was a source of pride.
But it wasn't just about money.
Friends said Cardin was part of the fabric that makes the Marine Corps such a famously tight-knit brotherhood.
Buddies of the fallen Marine described him as the kind of person who would give you his last $2, or his last cigarette.
"He was the guy I went to when I got in trouble. He seemed to always make things better," said Taj Saroya, who served with Cardin at Camp Pendleton.
Louis Cardin was an artilleryman -- first at Camp Pendleton, which allowed him to bring laundry home to his mother on weekends, and later at Camp Lejeune, N.C.
In March, his expertise was needed in Iraq, again.
Quietly, Cardin was flown into northern Iraq with about 100 other Marines and four artillery cannons from the 26th Marine Expeditionary Unit.
The Marines were staged on the Kearsarge and two other amphibious warships in the Arabian Sea, waiting for the call if it came.
The war against the jihadist group called the Islamic State, or ISIS, was poised to heat up. Iraqi and Kurdish troops were marshaling strength to challenge ISIS in its stronghold of Mosul.
Cardin went to a small fire base 50 miles outside Mosul.
The Marines and their cannons were supposed to provide extra protection against ISIS -- even though the United States is trying to keep American troops to a minimum, after pulling out in 2011.
Instead, ISIS fired rockets at the Americans.
U.S. radar provided some warning, and the Marines ran for cover when warning sirens sounded, according to a New York Times account.
Not everyone made it to safety.
One rocket missed, but another hit near Cardin.
He took the worst of it, in the chest. Eight other Marines were wounded, some bad enough to be sent home for treatment.
It took 40 minutes to airlift Cardin to a hospital in Irbil, where he was pronounced dead, according to the New York Times account.
At a speech in March, Marine Corps Commandant Gen. Robert Neller praised the staff sergeant for his actions that day in the clutch.
"He was leading his Marines in combat. They were in indirect fire and he made sure everybody got in the bunker. He just didn't make it in time," Neller told people attending a March Corps Association awards dinner in Washington, D.C.
"Is that sad? That's sad. But if you're going to go, you want to go in the fight."
Pat Cardin said Louis, the second youngest of seven siblings, was raised to keep an eye out for others.
"He heard from the time he was little, 'Watch that baby's safety margin!'" Pat Cardin said.
"I didn't realize it, but I was raising my kids to be Marines. In other words, making all your kids aware of watching their surroundings and watching out for the younger ones," she added.
Sometimes, like many Marines facing down combat, Louis Cardin talked about when death would come.
He wanted to die in the line of duty. But that wasn't all.
Cardin told people he wanted to go out in such a blaze of glory that it would make Chesty Puller, the most decorated Marine in American history, roll over in his grave.
"Louis had a sense of humor," Pat Cardin said. "He was always laughing."
Louis Cardin is buried in Riverside National Cemetery. He was the second American service member to be killed as part of Operation Inherent Resolve, the now almost two-year-old fight against the Islamic State.