Another in a series of occasional articles.

The road is crowded and tropical-hot. Bumping forward on a Humvee loaded with Marines, Chris Funk grips his M-16, muzzle pointed out toward the street. His blue eyes are locked on the world before him.

He sees shanty houses with rusted tin roofs and sidewalk stalls with metal pots of food. The city is Third World poor, it is steamy, it is jumbled -- a chaos of jitneys in motion, horns blaring, roosters crowing, people milling, foreign dialects.

Everywhere, eyes turn toward the Humvee, toward him.

Funk returns a steady gaze.

His sunburned face is sober, flat, all boyishness hardened by his four-pound Kevlar helmet with combat fringe. He scans the movements in the street, aware of the loaded weapon in his hand and the Marines beside him with assault rifles and machine guns.

They do not expect a firefight just now, on a hot Saturday afternoon, as they patrol near an airfield. But then, they are in a war against terrorism, and the rule is that there is no rule. Bad things happen. They happen with no warning, anywhere at all, the sinister mingled with the mundane and the ordinary.

They have happened here in the southern Philippines. Bombs have exploded near churches and restaurants. Hostages have been taken -- some beheaded. The brutality of late has come mostly from the Muslim extremist group Abu Sayyaf, which has been linked to Osama bin Laden's al Qaeda.

Funk does not take his eyes off the street. He has been in the Philippines for two months -- a private first class, in his first experience of war -- and the longer he has been here, the more real the danger has seemed.

He is 20 years old, a lanky kid from the Baltimore suburbs who grew up on soccer games and Sunday Mass and family vacations, the son of a State Farm insurance agent and a preschool aide. He had a job siding houses when Sept. 11, 2001, reordered his choices. "I want to be out doing something," he had thought.

Now he is halfway around the globe, among the first in his boot camp class to be deployed in the U.S.-led fight against terror. With him are Michael Garey, Brad Thomas and Jonah Harper, all part of the 3rd Marines, paths drawn together by a singular American horror that history would mark as a turning point.

The four are part of a generation that has come up through boot camp and training schools since Sept. 11 and who are now wondering whether they will join the war on terrorism or head to Iraq.

In Zamboanga City, Funk and the others find a first and early taste of life in a hostile zone. This is not the war of battlefields and tanks they have seen in movies. But at times the tension, they think, must be much the same.

'A New Age of War' The war on terrorism is not the soldier's war of old. Beyond the bombing campaigns and cave-searching missions of Afghanistan, it has played out quietly, in obscure places, dramatic moments often unchronicled.

Unlike many large conflicts of the last century, this has been a war experienced by the few, not the many. It is combat in the shadows, much of it grinding and anonymous -- even as President Bush proclaimed two weeks ago that it was advancing and vowed to "keep America safe" by going after terrorists "where they plan and hide."

But over the past 13 months, few lasting public images have emerged from distant battlegrounds like the Philippines, where the U.S. role has been limited, and so when Chris Funk and several other Sept. 11 Marines found themselves deployed, they knew only that this war would be different.

They did not know exactly how.

This, they would see slowly unfold over time.

"People think 'Thin Red Line,' or all-out war, the trenches or something," said Garey, two months into his deployment with Funk in Zamboanga. "This is a new age of war. This is a kind of war for the time it is."

The Long Calm In August, when he stepped off a C-130 in Zamboanga, Funk was immediately alert for danger. Until recently, he had not heard of this tropical outpost -- 500 miles south of Manila -- and he knew little at all about the Philippines.

Now he knew about an enemy. He knew about Abu Sayyaf.

Since January, as many as 1,200 U.S. troops had been based in the Philippines for an evolving mission to combat terrorism -- part military assistance, part humanitarian aid -- and prevent the island nation from becoming a haven for al Qaeda members on the run.

Funk's job as a Marine was infantry, but U.S. troops were not allowed in direct combat in the Philippines. Special Forces acted as advisers for the Philippine military. Funk's unit was responsible for security.

In the early weeks, Funk found this meant long days at Edwin Andrews Air Base, a place with coconut trees and farm animals and barefoot children, along with the usual runways and low-rise barracks.

For 12 hours at a time, Funk watched and waited for danger from a Humvee parked on a flight line where U.S. aircraft landed and took off. Alternating with another Marine in the turret, Funk manned an 84-pound machine gun pointed toward the airport perimeter.

On occasion, a C-130 would land with supplies. Then nothing. Hours passed. Breezes came and went. The sun went down; the sun rose. The heat persisted. Maybe another plane landed or left, maybe not.

On a remote Pacific island, with mosquitoes and malaria and soaking downpours, they conjured images of Baltimore and Texas and New York. They remembered their jobs before enlistment. The sports they played. The girls they dated. The wonder of cheese steaks and McDonald's hamburgers.

There were times when they stared at the horizon with admiration, watching the Army's Black Hawk helicopters swoop by and touch down, mighty rotors swirling overhead.

The choppers seemed to suggest action, places where more was happening.

They wondered if the choppers were bound to Basilan, an island just south that had been an Abu Sayyaf stronghold, with a history of combat and hostages.

In Zamboanga, for a time, this seemed remarkably far away.

On Oct. 2, part of the Marine unit prepared to head home. The men packed their weapons into a shipping crate. They imagined homecomings with wives and girlfriends and children.

The Sudden Storm The night of Oct. 2, while Chris Funk was on the flight line, one of his sometime duty partners, Brad Thomas, had orders to be an armed escort for military contractors making a run to an army base a few miles away.

Just before 7:30 p.m., Thomas was on his way back from the run. He looked out the window as his van passed a block of sidewalk stalls and shops. There was a tailor who made military uniforms and a cafe that specialized in beefsteak and a butcher who displayed meat on large, silver hooks.

He had been here before, and it seemed an ordinary day.

At 27, Thomas was older than Funk and had enlisted for one reason only: Sept. 11. On that day, he had a fiancee and a job as a manager of a steakhouse in Houston. He had been home, with a day off, in his apartment.

Horrified, he had sat for hours, transfixed by the television. That night, he and his buddies stood in a parking lot after their regular softball game, listening to a radio broadcast of Bush's speech.

For three weeks, Thomas rethought his life choices. He prayed to God.

By October, he was in a recruiting office, asking for infantry.

Now in Zamboanga, Thomas tried to keep his mind on the bigger picture. It was true that the work could get tedious, not just guard duty but the endless training that was the life of a Marine -- and it was truer still that he missed his fiancee, whose photo he hung near his bed.

Still, Thomas considered himself old enough to see that this was necessary, important.

That night, Thomas finished his duty with the military contractors before 8, then returned to the barracks and joined a group of Marines in a small room with a television and a giant American flag, near the dormitory of bunk beds where they all slept. The movie of the night -- one of the "Rambos" -- was all muscle and action.

At 8:30, a call came in for the commander, Maj. Joseph T. McCloud.

In a matter of seconds, someone ran into the television room.

There had been a bombing.

Thomas ran for his gear, thinking it must be another drill.

Within minutes, it was clear this was the real thing. The casualties, Thomas learned, included two U.S. soldiers who were sitting at the cafe he had passed in the van an hour earlier. "I was just there," he thought.

Now the cafe was blown apart. So were adjoining shops. Four people were killed in the chaos. More than 20 were injured, including another U.S. soldier.

Thomas and other Marines went out to stand watch on a military base where the soldiers had been taken.

Then Thomas was in a van again.

Now the body of the slain U.S. soldier lay beside him.

Just hours before, the soldier had been all gusto and future, a Green Beret commando, part of the U.S. military elite: Sgt. First Class Mark W. Jackson. He had stopped for dinner with a fellow soldier at a cafe where members of his unit had grown close to the mom-and-pop owners.

That particular night, a homemade nail bomb had been planted nearby on a parked motorcycle. "This man eating dinner lost his life," Thomas thought.

The soldier would be returned to the United States in a flag-draped coffin, flown on a military plane like those that he and other Marines guarded every day.

In the dark of the van, the loss felt personal, though Thomas had never known his slain comrade. This was, he would come to decide, the closest he had ever felt to Sept. 11. "I wasn't in New York when it happened," he reflected, "but now I've seen it."

Waiting, Watching The hidden enemy struck again and again. A day later, there was a bomb that exploded near a church. Seven days after that, a bomb was found inside a jitney and defused. Two days went by and another bomb was found -- before it detonated -- near a market.

At the same time, the Marine unit got word of a threat against U.S. aircraft -- with an American C-130 due to land.

To boost security, Funk and six other Marines were told to jump on a Humvee and patrol the nearby streets of Zamboanga, weapons loaded, helmets on. This would be all of the usual vigilance, and more.

No one knew if this was a scare or the warning of a real attack by Abu Sayyaf.

Just two weeks earlier, a senior leader for the Islamic militants had vowed more terrorist attacks in the mostly Catholic Philippines and called on other Muslims to strike at "enemies both foreign and local."

Now, as the Humvee barged down streets near the runway, Funk and the others kept their weapons pointed, ready for the worst.

Sober-faced, in battle gear, they looked ready for war -- which was the point. They were. If something happened, they would fight.

The C-130 landed safely and took off again.

By now, the Marines who had once been headed for homecomings had unpacked their weapons and settled in again. Funk was reassigned to the unit's crisis-focused "quick reaction force," along with a boot camp classmate: Garey, 20.

Both Funk and Garey had lives that harked back to Sept. 11. That life-altering day, Garey had been on a roofing job in Buffalo and come home that night to find his family in tears -- his stepmother, stepsister and cousin.

The next day, he called his recruiter. He had planned on boot camp for a long time, but kept getting sidetracked. "How soon can I go?" he asked on Sept. 12. It was time.

Now, part of "Operation Enduring Freedom," Garey considered war almost philosophically. The war had to be geared to the enemy, he said. "We're in combat here, but it's just a different kind of combat," he ventured one humid night, in camouflage pants and a thin T-shirt.

Tall and quiet, Funk listened as his friend spoke, then wondered whether this might be "the hardest kind of war because you don't know who your enemies are."

Still, thinking back to cinematic images of World War II and Vietnam, he reflected: "Now war is sitting around and waiting for something to happen. It's more security."

Funk himself had taken a long look at a "wanted" poster of Abu Sayyaf leaders that hung in their barracks. He had quietly wondered whether he would recognize them amid the throngs of people he saw in Zamboanga.

Proximity of Danger One moonlit night in the tropics, Funk called his mother in the Baltimore suburbs. He used a phone in the rec center -- a portable unit with a pool table, chessboards, movies, newspapers, e-mail access, popcorn for the asking.

"There was a pretty big bombing pretty close to where you are," Barbara Funk told her son, mentioning the Bali explosion that left nearly 200 dead and was linked to al Qaeda.

This registered only mildly for Funk, in spite of the relative proximity.

He asked his mother about the Washington area sniper. He had heard about the killings and wanted his family to be careful; they were not far removed from the path of violence in Maryland and Virginia, which was still going on.

There was a grim commonness from worlds apart -- random violence, caution against what may lurk within the benign and routine.

For Funk, the idea of combat had been alluring since he was a boy of 6 with GI Joes. Growing up, he hunted with his dad, played soccer and lacrosse and basketball. Always, the military seemed a possible path. One of his favorite uncles was a Marine.

Still, only Sept. 11 had made the choice clear. Funk was leaving behind a close-knit family, his 2000 black Mustang and a newfound love for boxing. He was trying to ignore friends who said they would never do the same. "I'm not going to die," they told him.

On Jan. 2, Funk left the Baltimore suburb of Reisterstown with his mother heartsick about the danger he might face. His father, who had warned his mother against tears, surprised himself by crying at the door.

Just 10 months later, Funk is stationed in the Philippines and reading "Black Hawk Down," which he has already seen at the movies, about the 1993 firefight in Somalia involving U.S. Rangers and Delta Force commandos.

He is on Page 153 and finds it sobering. "I wouldn't want to lose another Marine," he reflects, sitting on the foot locker near his bunk in his unit's borrowed barracks, located on the Philippine air base.

Death seems more possible here.

Funk and the other young Marines have grown closer in Zamboanga. They live in spare two-story quarters with enough room for the unit's 40-some men, and Peanutz and Skunks, two nap-loving adopted dogs. In the doorway, a black flag with a skull and crossbones warns: "U.S. Marines" and "Mess with the Best. Die like the Rest."

One day during a brief lull, the conversation upstairs drifts toward Iraq, where they could conceivably find themselves deployed one day. Although no one has any certainty about this, they are infantrymen, and this deployment is nearing its three-month end.

"We want Iraq," one Marine says.

"A childhood dream," jokes another.

Life here has taken on a pace and rhythm of its own. Weekends mean work. Free time means an hour at the gym or a game of PlayStation football. On Sundays, they are allowed two San Miguel beers -- if they are 21 years old. For their own safety, they are not allowed off base, except when they are performing work missions.

Most know little about Zamboanga's 600,000 people.

Those they probably know best are children who live on the base too -- and hang out near the U.S. barracks, vying for jobs shining boots. The few dollars some take home rival the earnings of many parents in Zamboanga.

"Sir Garey, shine your boots?" one sings out, then another, to Michael Garey, Funk's classmate from boot camp.

One evening, Garey looks on as a teenager plays a guitar outside the barracks. He asks to have a try. The collaboration goes so well that Garey gives the teenager pesos to buy the young Marine a guitar of his own -- which he does.

In the evenings that follow, Garey learns more. One song he comes to know best, he has learned from the teenager. He plays it often but never catches the name.

Helping the Fight The morning is hazy when they set out in another convoy of Humvees, north through Zamboanga, onto the dusty road to Cabatangan. It is Oct. 14. It is hot like July. They are wearing flak jackets and helmets and long sleeves, M-16s loaded and raised.

Today they will collaborate on the details of war, hoping to help their Marine counterparts in the Philippine military.

The Humvees pull up to a white compound that looks like a mosque, with white minarets that stand out against their jungle-green surroundings. The building is set on a gentle rise, with mountains behind it.

Closer in, it is an eerie symbol of religious war, with bullet holes along the imposing white walls and a machine-gun position out front. The roof has been blasted by mortar fire. Until a year ago, it was occupied by members of the MNLF, a Muslim separatist group.

Now it is a base for Philippine Marines, who have been part of the battle against Abu Sayyaf. Two days earlier, they took especially heavy casualties -- 11 men killed on the island of Jolo, about 60 miles away.

The U.S. troops arrive with combat refresher classes -- on the M-16, shooting positions, the M203 grenade launcher, mortar techniques and light machine guns.

Chris Funk, a relative newcomer to military life, finds himself in a small group demonstrating the fine points of cleaning an M-16 to Noel Buita, 32, a combat-hardened corporal who has fought the Abu Sayyaf.

"If it gets dirty in there," says Funk, pointing to a hard-to-reach crevice in the rifle, "your weapon can seize up."

The Philippine corporal nods politely, working his weapon with a cleaning fluid that he and others cannot afford to buy. He knows how to clean a rifle, of course, but seems interested in Funk's attention to detail and the bounty of U.S. supplies.

An hour later, Jonah Harper delivers a lecture on the M249 SAW, a light machine gun. Harper only enlisted after Sept. 11 but talks like he has spent most of his life with the weapon.

Some of the Filipinos take out paper and make notes.

"I've fired 1,500 rounds," Harper assures them, "and it's never jammed."

The Philippine Marines gather around when he finishes, hoping to see a weapon not yet in their arsenal. There are questions. How much does it weigh? Could a left-hander use one?

Harper comes away feeling a step closer to the action. "They're going to fight the battle," he says. "They're going to Basilan to fight the Abu Sayyaf. If we can help these guys, it's a huge thing."

Keeping Watch On a Wednesday in mid-October, the Humvees roll again and Funk finds himself in unfamiliar surroundings at an elementary school in a mostly Muslim city neighborhood called Campo Islam.

As part of a humanitarian aid program, 800 children and parents will receive dental care -- many for the first time -- in a school community where there is one textbook for every five children and 50 students for every teacher. Here, dental care means pulling rotted teeth. Nearly everyone who comes for care needs an extraction. There is no cleaning offered, no filling cavities -- no time or money for that.

Funk stands at one corner of the schoolyard, with a loaded rifle, guarding against any possible terrorist strikes, sweat dripping down his face. In the heat, the smell is pungent -- maybe garbage or sewage or discards from a nearby fish market.

He watches everyone -- how they move, what they carry. By the next day, he would discover that Abu Sayyaf was at work again -- planting bombs and taking lives, with two explosions claiming seven lives and 150 other casualties.

For the moment, though, it is a hot day in a schoolyard where nothing appears amiss.

Funk imagines the family living in the house he is looking at -- whether they built it themselves, how they get by, if it is good for people to consume the food in market stalls or the water that the Marines cannot drink.

The U.S. forces get much of their food flown in, and drink bottled water.

In another corner of the schoolyard, Harper stands guard, eyeing all movements at the back of a school building.

Harper worked as a Hibachi chef in a Florida restaurant until after Sept. 11. That day, his sister's teacher lost her daughter, a flight attendant, on one of the hijacked planes. He enlisted Oct. 10, 2001.

"I was mad more than anything," he said. "No one who was killed that day had anything to do with the terrorists."

Now, in Zamboanga, three Filipino teenagers approach him admiringly.

They ask, in fairly good English, what he thinks of their city.

"Traffic here is pretty crazy," Harper admits. "The first time I was driving I said, 'Whooah!!' "

The teenagers laugh.

"Are there jeeps in America?" they ask, having noted the Humvees.

Harper pauses to think about what they mean.

"No," he says. "No jeeps. Mostly cars."

They point to his large weapon.

"Is it hard to carry?" they ask.

"In the beginning," he says. Then he jokes: "You need muscles. Little, skinny guys get pistols."

They laugh more.

How many bullets?

"Two hundred," he says, matter-of-factly.

Their eyes widen.

One of the teenagers, Vas Abubakar, announces that he plans to be a Marine. He and his friends, JunJun Caalim and Julius Agabin, are all 18.

Harper smiles appreciatively.

"We joined," Harper says, pointing to several other U.S. Marines, "because we want to help fight terrorism."

"Is there terrorism in the United States?" asks Abubakar.

"Yes," Harper tells them. "There is terrorism everywhere."

Pfc. Chris Funk, who quit his job siding houses to join the Marines after the Sept. 11, 2001, attacks, patrols the streets of Zamboanga City, Philippines. The Marines aren't allowed off the Philippine air base except during missions, leaving Pfc. Michael Garey plenty of time to learn how to play his new guitar. Rodolfo Enriquez, 60, was injured in an Oct. 2 explosion outside his restaurant in Zamboanga City, Philippines. The blast killed a U.S. soldier who was stationed at nearby Camp Enrile and two other people.Lance Cpl. John Esparza, 20, from Festus, Mo., talks about weapons maintenance with Sgt. Erick Lalata of the Philippine Marines. The U.S. troops' anti-terror mission is part military assistance, part humanitarian aid. U.S. Marines stand guard at an elementary school during a humanitarian mission in the Campo Islam section of Zamboanga City, Philippines. There is much to keep an eye on, but little appears out of the ordinary. Pfc. Jonah Harper, 20, of Fort Walton Beach, Fla., stands guard as a C-130 unloads goods and more Marines.