The Marines are filthy and tired and act hard, like they've been here two years instead of two months.

Charlie Company's 200 or so infantrymen -- half from Connecticut -- are reservists, pulled from civilian life for the unit's first trip into the war. They will spend seven months running patrols, guarding posts, raiding suspect houses and manning checkpoints in one of Iraq's most dangerous cities.

The men from Enfield, Colchester, Middletown and East Windsor are fighting in Fallujah to keep things from getting worse. They fight to buy time for the training of Iraqi replacements. They fight for an unknown future under yet-to-emerge Iraqi leaders. And, at the most basic level, the corporals and privates first class fight to keep themselves and their friends from getting killed.

They rehash their battle stories sometimes before they've returned to safety, writing their own characters into the war movies they gravitate to. They court death in their spare time, watching violent movies and some playing video games of war. Under it all, they are young and far from home.

``We're trying to keep Fallujah stable and get out of here,'' said Cpl. Parke Stearns, 26, of Lebanon, Ct.

The Marines here are fighting a war. But it's not always clear whose war.

Charlie Company is based at the Civil-Military Operations Center, or CMOC, pronounced see-mock in the acronym jungle of military speak. The compound is at the center of the city, facing the major east-west route through it. Charlie Company owns downtown, the worst of Fallujah. It is one company where four battalions with thousands of troops once operated. The nearest Marine company, another part of the 1st Battalion, 25th Marines, known as ``New England's Own,'' is at the train station on the northern edge of the city.

But there are other supposed allies. Iraqi police, most of them locals, work from stations scattered around Fallujah, driving little pickups with patches of steel welded to them for armor. Three Iraqi Army battalions -- increasingly trusted by their U.S. partners -- also operate here, brought in from elsewhere.

The area is a stronghold for the Sunni branch of Islam. The Iraqi Army soldiers are mostly Shiites, so they are among the insurgents' favorite targets. While the Iraqi police are mostly Sunni, their partnership with American occupiers invites attacks on them, too, leaving them walking a crooked line.

As 1st Sgt. Ben Grainger, Charlie Company's chief noncommissioned officer who is from Enfield, said, ``They live in the community, the same community the insurgents live in. It's not a matter of them dying; it's a matter of their wife, family and kids dying. They're almost forced to play both sides.''

When working with either security force, Grainger said, Marines are told, ``Treat them as our counterparts, but be ready to kill them, if necessary.''

On May 19, a car on the ``new bridge,'' the main crossing over the Euphrates River, rolled up to the point of the bridge where Iraqi soldiers sat in a sandbagged post. It detonated, tearing the car and suicide driver into hunks of black shrapnel. Only one of the soldiers was wounded in the explosion that wrecked two of their armored vehicles, but the blast also punched holes through the bottom of the bridge, knocking it out until it could be repaired.

Soon after the attack, Iraqi soldiers milled around, laughing and taking pictures. One of them showed off a plastic bag that held a license plate. He signaled that the other item in the bag was the blackened foot of the driver.

That evening, as engineers checked out the bridge, another company from the battalion watched the area. They came across a group of men who scrambled into vehicles and fled. Chasing down one of the cars, a taxi, the Marines watched its driver run the car into pedestrians before bailing out into a building.

Charlie Company responded as backup, to help surround a section of the notorious area of town known as the Pizza Slice, a triangle formed by two main roads and the river. Inside the taxi, Marines found a few automatic weapons and a rocket-propelled grenade launcher. Night fell on their search, which ended with a suspect who fit the description, but couldn't be held without more proof.

As they prepared to leave, a few shots popped in the distance across the adjacent cemetery. The Marines who heard barely reacted. Bullets are almost as common as mosquitoes when the sun goes down in Fallujah. But the Marines carry night-vision equipment. As they like to say, ``We own the night.''

The following day, again, a suicide car bomb struck. This time, it hit an Iraqi police station. The car blew up at the outer security perimeter, injuring some people there, but no officers.

When Iraqis are hurt or killed in the city, it slides off most of the Marines in Charlie Company. It's when their own get hit, as they have a few times in the last several weeks, that the news grips tight.

On Wednesday, Marines from Charlie Company's 2nd Platoon are returning to base when an Iraqi boy, maybe 11, throws a grenade at them. It lands within lethal range but doesn't go off. The boy gets away. Explosives disposal guys are called in to grab the grenade. They arrive with a flat tire, so more Marines from 2nd Platoon come out for security.