The arched, four-column facade of the Plymouth Apartments at 11th and N streets NW used to give the old building a stately elegance.

Now it forms the macabre portal of a large crypt, a dilapidated, nightmare of a structure where heroin addicts slum in a basement shooting gallery. At least 24 persons have nodded off into heroin overdoses in and around the Plymouth this year, several of them fatal.

Matthew Henson was found dead here July 31, sprawled on his back in a puddle of rubbish and discarded syringes, the 50th person in three months to die of a heroin overdose in Washington. The toll now stands at 72 for the year, 10 short of the all-time high reported in 1972 and 10 more than were recorded in all of last year.

Inside Henson's home at 50 L Pl. NW, just over a dozen blocks away from the Plymouth, relatives mourned. Matthew was the second oldest of 10 children, a construction laborer who was unemployed.

He had dropped out of Dunbar High and enrolled in the Washington Urban League's "D.C. Street Academy," but did not graduate from there either. Later, he joined the Army and worked as a cook in Guam and at Ft. McNair here.

He had been using heroin for about three years; he was dead at 25.

"I didn't get a call from the morgue until the next day because he had somebody else's ID on him and they had him labeled 'John Doe,' " recalled Rose Henson, the victim's estranged wife. "The autopsy showed that he had so much stuff in his system that he probably had somebody shoot it up for him."

Spend a few days at the Plymouth during "feeding time" when the addicts arrive to shoot and be shot. Talk to those who try to live here between the rapes, the beatings and the overdoses, the constant sirens in the night, the break-ins. Watch the flow of zombie-like addicts, some dressed only in their underwear, who stumble about watery-eyed and with swollen limbs, scratching themselves, rotting their lives away.

Call this place The Rock, says janitor Walter Evans. Life here is just that hard. Better yet, call the Plymouth what it is -- a tomb for the living dead.

It is 11:30 a.m., breakfast time for the junkies who congregate outside Apartment 104 in the heat of a steamy summer day rank with mildew and body funk. Syringes and blood are strewn on the concrete floor.

Two eager women in their mid-20's with long blonde hair -- one in a purple halter top, the other wearing a torn Villanova University T-shirt, both with faces that are cracked and stained with dirt -- are escorted to the door by a youth in jeans and a white T-shirt. The skin across his forehead is creased from the stocking cap that covered his slicked down hair only moments earlier.

The women are among the first to arrive this morning and the youth is heard to promise them satisfaction. He has some "Murder One," he says, referring to the new, more potent bumper crop from the golden crescent of Iran, Afghanistan and Pakistan, the powerful heroin that has helped drive the city's heroin overdose rate to a record level. The girls smile with the dull yellow of morning teeth and head for the basement.

"Them dudes is tripping -- sho nuff," remarks one of the tenants, sitting on the front steps, watching the traffic begin.

"It's killing 'em like flies," her young companion replies.

"That's good," the woman chuckles. "That means it will be more money and more food for the babies."

A young black girl about 15 years old, with a baby in one hand and $15 in the other, sashays up to the apartment building. The older woman on the front stoop tries to dissuade her from going downstairs.

"Buy you some white socks," the woman says, pointing to the ulcers on the girl's legs--ugly, open scars of frequent heroin use. "Or maybe buy some food for your baby. You gonna die if you keep doing that stuff."

"I'm gonna die, anyway," the young girl says nonchalantly. "I got sickle cell."

Life in The Rock caters to low-income residents who are stacked into nearly 70 units towering seven stories above 1236 11th St. NW, now closer than ever to the new, expanding downtown Washington. Residents say that the elevator hasn't worked for about six months. And last week, they say that when one of the apartment's oldest and better known residents was found dead in her bed, a crew of paramedics had to "walk" her body ingraciously down six flights of narrow stairs.

While most of the drug activity is concentrated in the basement, where there are four apartments, three of which are vacant, residents say the entire building is infested from top to bottom.

"I live on the seventh floor, next to the roof," said one woman. "I can hear them all night. What's really scary is when you can hear them breaking into vacant apartments, tearing down doors."

Other residents add that when they call police anonymously, they get no response, and when they give their names, police arrive at their apartment door in uniform--fingering them as snitches.

"Now that ain't cool," another woman complained. "They don't care about nobody but themselves."

Walter Evans, who sweeps the front steps and changes fuses for those who fear to tread in the addicts' basement lair, says he cannot remember things being this bad at any other time during the 10 years he has lived in The Rock.

"I'd say about 200 addicts a day come in here and you get all kind of nonsense as a result," Evans said the other day. "There are all kinds going down there -- young, old, black and white. I even saw them carry a crippled man down once. This kind of stuff is dangerous for the people who pay rent here and the police don't seem to be able to do nothing about it."

Local youths in the area, particularly athletically inclined teen-agers, once had the junkies on the run by periodically pelting their hole with rocks and bottles. But after one of the youths was caught and pistol-whipped, the addicts easily reclaimed the turf.

It has been like this for about nine months now, residents say. The Plymouth, located a few blocks from one of the city's major on-the-street heroin markets, has become a refuge for addicts seeking to beat the heat of Police Chief Maurice T. Turner's crackdown on drug trafficking.

Once a shooting gallery opens and drug use moves indoors, police spokesmen say, law enforcement becomes more difficult.

"In the case of a shooting gallery, you need a search warrant, and to get that you need probable cause--which means we have to get an informant or a police officer inside," said Sgt. Leroy Croghan, a D.C. police narcotics detective. "And he has to be inside while the activity is going on. What adds to the problem is that once you close down an establishment another one opens, usually in the next block."

The Plymouth is just one of numerous shooting galleries scattered throughout the inner city. Overdose victims are rarely found in the galleries themselves, which in some cases are set up as comfortably as a room in a suburban rambler. More often, the bodies of addicts who don't regain consciousness after shooting up are dragged out into hallways, back yards, or vacant, trash-strewn rooms and stacked up until the morgue wagon arrives.

Croghan said that police were aware of the situation at the Plymouth, but declined to comment specifically because of a "major" investigation of heroin sales in the area.

However, it is common knowledge among law enforcement officers that "shooting galleries" often serve as "fly traps" that lure a variety of criminal suspects who can either be apprehended on the scene or who lead them to bigger flies.

To watch the Plymouth shooting gallery in operation you need only peer into Apartment 104 through the still blades of a window fan.

The inside of the apartment, when viewed that way, is a devil's kitchen of heroin paraphernalia: syringes still in cartons marked "For Diabetic Use Only;" soda straws, apparently cut to order, for sniffing heroin; aluminum foil on which heroin is cooked and smoked (called "chasing the dragon") and a blue, plastic bottle top large enough to fit a quart-size Mason jar brimming with a chalky, white powder.

Inside, a woman with bruised arms sways in and out of a doorway, watched by several men dozing on cots and in easy chairs.

Seated conspicuously in the corner of the sparsely furnished living room is a large woman with a dirty pale complexion, who wears a black head rag, short pants that are unfastened and sandals that bulge from the pressure of her swollen feet. A pet black snake a yard or so long is curled around her neck and arms. When she discovers someone peering into her living room, she raises the others from The Nod.

"What you want?" someone yells.

The reporter responds with the name of the woman who, according to rental office records, rented Apartment 104 in 1979. At the time she signed the lease, she listed her employer as the D.C. Department of Human Services.

"Don't live here," someone yells.

"We've been trying to clean out that apartment for three months," said a spokesman for the William J. Davis Real Estate firm, which manages the Plymouth. "But the eviction process takes time."

The women tenants who congregate on the front steps of The Rock, and assist the janitor in sweeping trash and picking up bottles from off the walkway huddle for defense against the onslaught of junkies, rocking their babies in buggies, trying, out of fear, to mind their own business.

That is difficult to do when heroin dominates the scene. A mother suddenly realizes that her daughter, barely able to walk, has wandered a few doors down the sidewalk hand in hand with a junkie who was playing like he was the father.

"Girl, you better get your baby," the negligent mother is scolded by another woman.

"I just looked up and she was gone," the woman says, naively.

"Stupid, girl," she is told.

By now, the junkie has abandoned the child at curbside and jumped into a dusty, black Eldorado with a shredded convertible roof. The car, bearing Virginia tags, is driven by one of the women who had just come out of Apartment 104.

No one around The Rock a week later could recall Matthew Henson. Too many addicts come and go. Too many people mind their own business.

"I stay away from junkies," testified a 10-year-old girl, to the reassuring smiles of the older women sitting on the front steps of the Plymouth. "I seen one in the hallway with a needle stuck in his hand. He was dead."

By her recollection, that was the night Matthew Henson was found dead, although two other overdose cases, ultimately nonfatal, were also reported that night.

"Matthew was a real nice fellow," recalled his sister, Natalie Henson. "But when he came back from the service he had become real independent and nobody could tell him what to do. He was just like most of the other men who grew up around here. And they're all dead now."