On a raw and rainy Tuesday last winter, Robert Emil Moens packed up his belongings in a dirty green sack, fled the flophouse on Rhode Island Avenue where he had spent the night, and trudged up 16th Street NW past Malcolm X Park to a three-story row house on Park Road.

At age 25, he was quite used to suffering, this slender man with oily brown hair, pale green eyes, no job and no home. He ate in soup kitchens, sheltered himself from the daylong chill by hiding out in bookstores and libraries, and slept where he could, indoors and out, with the winos, derelicts and lice. Peace came to Moens only within the dreary confines of a newspaper shack on 18th Street near the World Bank, a few blocks west of the White House. There, at least, he had a little bench to sit on, a few cans of soup and two plastic jugs -- one filled with water, the other for relief.

But now, as he crossed Park Road and made his way to the seventh row house on the left, Moens realized that it was his future that mattered, not the present, a promise personified in the figure of Friar Jack, a lanky cleric who stood in the doorway of a place called McKenna House like Gabriel at Heaven's gate, welcoming him with a handshake and a clap on the back.

Wearing dirty black trousers and a frayed cotton jacket, Moens stepped inside, his eyes wide with wonder and curiosity as he viewed this marvel of renovation. The odors so familiar to him, whiskey and urine, were replaced by aromas of rose water, new carpets, baked chicken and rice. Several buddies from the street were already there, including his chess partners, Bryan and Charlie. As strains of rap music and jazz resounded through the house, Moens and the others explored the treasures of their new-found home.

They roamed from floor to floor, peering in one door after another, finally settling down in the second-floor living room, where Moens flicked on a console color TV set and tuned in a "Bugs Bunny" cartoon. Relaxing in a plush sofa, his feet resting atop a coffee table, he sucked on a cigarette and proclaimed: "I hope I'll know how to act here."

Friar Jack, dressed in jeans and a flannel shirt, stood in the foyer, calmly surveying the scenes of delight unfolding before him. "This is the last chance," he said of his new flock. "If they don't make it now, they have no excuses left."

So began McKenna House, a remarkable social experiment exploring the mystery of human failure and the possibility of human redemption.

The proposition was this: What would happen if you took a group of homeless, jobless men, who were accustomed to eating in soup lines and sleeping in public shelters, and placed them in a middle-class environment? If you screened the candidates carefully, put them under the watchful eyes of four men of God, fed them three meals a day, gave them new wardrobes, job counseling and every opportunity to right themselves, could they find work and ultimately reenter a society from which, for many varied and untold reasons, they had totally withdrawn? Dissimilar Societies

This series of stories is about the experiment -- the adventure -- at McKenna House, a residence atop Meridian Hill where Robert Moens and 14 ragged friends converged with Friar Jack and three other Catholic clerics Feb. 28 to begin divining answers to those questions.

The cast represented two societies that at times seemed almost comically dissimilar. On the third floor lived the white, celibate friars with their mass vestments, books of Catholic theology, and a marble bust of their patron saint, Francis of Assisi.

Below them, on the first and second floors, lived the poor, street-weary souls with nicknames like "Wild Bill" and "Razor Blade," whose language was often earthy enough to embarrass a fullback, not to mention a priest. In their rooms were possessions they valued no less than the friars valued theirs: Sony Walkman radios, chess sets and Playboy magazines.

Despite the contrast, all 19 were joined in their mission: Jack and the friars hoped to reacclimate their clients to the ways of working society while maintaining their own brotherhood of faith. Moens and the other men hoped to progress in the most rudimentary of ways, to learn to bathe regularly again, dress in clean clothes, eat meals with knives and forks instead of hands, write resumes and find steady work.

At issue were two distinct challenges of human rehabilitation -- one economic, the other psychological. Unemployment and homelessness were symptoms and causes of the suffering, and as the friars attempted to teach the men how to dress for success, they would encounter one long-submerged trauma after another. An experiment that at first centered on whether a man could find a job later became tied to more important matters of health and emotional well-being.

But on opening day, McKenna House was still a simple proposition laden with excitement and pristine hope, all of which was celebrated late into that first night. At 5:30 p.m. the 19 men, with Friar Jack at the head, formed a long and merry human chain to distribute $2,180 worth of towels, blankets and sheets that were hand-delivered by a little fellow from Sam Kugler's House of Fine Linen.

At 6:30 they gathered in the dining room to feast on a first supper cooked by the house chef, a stout Dominican woman who called herself Sister Maria. The meal was graced at 7:30 by a big chocolate cake that one of the friars had procured from a neighborhood bakery at a discount price; that it proclaimed "Happy Birthday" to some unknown "Ishram" did not seem to matter at all.

Finally, at about midnight, Moens and his mates retired to their bedrooms unsure about their futures but recognizing that something profoundly different was happening, that they had reached a turning point in their lives best symbolized by the unaccustomed warmth in which everyone slept that night.

Outside, it was 39 degrees. Inside, it was 65. The Search Begins

The preparations for McKenna House actually began several weeks earlier in another part of Washington, inside a creaking, crumbling, four-story building called Calvert Emergency Shelter. Supreme Court Justice Edward D. White lived in the same structure at the turn of the century, but now it smelled of mildew, tobacco smoke and booze, and often was a very violent place.

It was there, last winter, that Friar Jack Pfannenstiel and his comrades began their search for candidates in the experiment.

The four clerics operated the shelter, where each winter night 63 homeless men convened to read, watch television, play checkers, cards and chess, and sleep on waterproof, plastic-covered mattresses. As a cross-section of Washington's homeless subculture, they provided a wide array of personalities from which the friars could choose.

There were petty thieves who tried to make a living by selling hot wristwatches and Panama hats, and there were long-haired derelicts sporting years of muck and filth. There were young Latinos, some of whom arose before dawn to earn $3 by reserving spots for sidewalk vendors. And there were the mental outpatients, the most prominent of whom was a shoeless, bald and very thin character who called himself Pat Russ Jake Poe.

"Spare change for the ment-ly deranged!" he often cried in the smoke-filled stairwell, hoping someone would drop a few coins in his palm. No one ever did.

Often he was stationed next to a guy named William who suffered an apparently permanent case of lice. No matter how hard anyone tried to persuade him to delouse himself, he refused. He said he liked the bugs. Each one had a name.

Amid this distressed crowd Friar Jack seemed out of place. He was a lean, rangy and clean-shaven fellow of 31 who was raised on a family farm in Kansas and was ordained a Roman Catholic priest on May 21, 1982, after a decade of study and community work in places as far-flung as the cells of the D.C. Jail and the hills of West Virginia.

Friar Jack was working as the assistant pastor of a poor inner-city parish in Baltimore when he received a call from John Carr, secretary of the Office of Social Concerns of the Roman Catholic Archdiocese of Washington. Carr told him about the plans for McKenna House and wanted to know if the friar would be willing to run it.

He did not know what to say. He was content in Baltimore, where he had helped set up a free food cooperative for the city's poor and elderly. It was the sort of work mixing piety and social concern that first attracted him to the priesthood; the subject of his master's thesis was South American liberation theology and thought.

But after thinking Carr's proposition over for a few days, he decided to accept the new assignment. For one thing, he was still feeling considerable pain from the death of his older sister, who had died suddenly after suffering a massive cerebral hemorrhage back home in Kansas. A change in direction might help, he thought. He had been quite close to his sister, and her passing was a cruel reminder of the fragility and fleeting nature of human life. There seemed so much work to do and so little time.

He also saw the crisis of urban homelessness as a new challenge for the church, and McKenna House promised to be not only a bold new response to the problem, but also an adventure of the mind and heart unlike any other. That was especially appealing to Jack, a member of the Capuchin Order of Friars, a 459-year-old Roman Catholic brotherhood that stresses the ideals of charity and self-sacrifice.

So Friar Jack came to Washington on June 30, 1982, and immediately immersed himself in the city's homeless subculture to get ready for McKenna House. He visited soup lines, downtown heating grates and other hangouts and became a familiar visage, a young fellow with a long gaunt face and horn-rimmed eyeglasses who would listen to the bums' stories and lend words of sympathy.

There was nothing self-righteous or sanctimonious in his speech or bearing. He laughed at the men's jokes, no matter how dirty, and was not fazed at all by the ugly words they often used. He was at ease joining them for coffee at McDonald's and hanging out late at night beneath the portico of Constitution Hall, where quite a few of them slept.

If there was one peculiar thing about him, it was his unnerving penchant for walking. Friar Jack could walk nonstop for three hours or more and never get tired. He was renowned for taking long, one-on-one strolls in the cold night air, up and down Connecticut Avenue, where two men -- one lanky and clean, the other often threadbare and disheveled -- disappeared amid the rush-hour traffic of pedestrians heading home from work.

One day he was invited to the White House by a Reagan administration aide who had taken an interest in the McKenna House idea. Friar Jack showed up in his best brown habit and discussed the plight of the homeless over lunch in the White House cafeteria. He did not consider himself naive, really, but still he could not get over the surprise he felt sitting there among the wielders of American power. They were all white and male, and the help in the lunch room was virtually all black. He could not explain the vague sense of disappointment and sorrow he felt.

Everything he learned he passed on to the Catholic faithful. Like a politician on the stump, Friar Jack went out to a different church every Sunday morning in his brown hooded robe to drum up financial support for McKenna House, which was to open in a few months. His sermons were filled with anecdotes, his most poignant story the one about an unemployed air traffic controller he found living in the streets. The man was fired during the 1981 strike, lost his house and car and was separated from his wife and children.

"Many of these guys just need a break," he told the parishioners, his voice brimming with idealistic sincerity. "McKenna House will provide a way out." Reality Sets In

At the Calvert shelter last winter, before McKenna House opened its doors, Friar Jack's brotherly idealism clashed with an ugly and hard-edged reality. His apprenticeship was a gritty, night-by-night struggle that was recorded in the form of a nightly journal he decided to keep. Entries such as these were penned by him and his compatriots in the Calvert logbook for the winter of 1983-84.

Dec. 13: Had problems with Kahlil. After a confrontation in which violence was threatened, police were called. Before they arrived he left, threatening to teach my "bitch ass" a lesson.

Jan. 26: Carlos was having a nicotine attack and got violent. He kicked Daniel in the head.

Jan. 28: Victor had a serious knife wound. Awaiting ambulance to take him to GW emergency room.

Jan. 31: Terry was arrested on disorderly conduct charges. He called from the police station at 3 a.m. asking to be bailed out. I eventually went down to the station and got him.

Feb. 3: Walter came by and said he was not going to stay here anymore because of the bugs. He said he can fight the men and win, but can't fight the bugs because he can't see them.

Feb. 21: We have a rat in the house. It's about the size of a Buick.

The longer Friar Jack worked at the shelter, the more confident he became in the harsh environment, reaching a point where he felt comfortable enforcing rules of behavior. "If you're drunk you're not welcome," he shouted each night to the crowd of shivering men waiting outside for the doors to open. "If you've been smokin' reefer, shootin' dope or snortin' coke, you can't stay here."

Gradually he began to see a peculiar irony in the way his charges suffered. One night he was watching the news on television when he was informed that one of Calvert's mentally disturbed denizens had been arrested and sent to St. Elizabeths Hospital for hopping the White House fence.

"Maybe that's what a lot these guys oughta do," he said, figuring it to be the only way Calvert's outpatients could get the treatment they needed.

As Friar Jack learned about the men, they learned about his purpose. Despite his best efforts to keep it a secret, word quickly spread that a curious event was about to happen. Soon, somewhere in Northwest Washington, a renovated row house managed by Friar Jack was going to open its doors and provide shelter, jobs, meals and clothes for 15 lucky men.

From mouth to mouth, the rumor traveled in the streets of Washington to a point where the place eventually became known simply as "Kenny's House," a mangled version of the true name. In time it was viewed with an anticipation rivaling that which prospective lawyers must feel while awaiting results of the bar exam. The cold and fetid air at Calvert was electric with suspense as the men discussed the promise of McKenna House and hungered for news of those selected.

"I saw Odell going for a walk with Jack," a young drifter whispered to a friend at Calvert one night, taking it as a sure sign of Odell's anointment as one of the chosen few.

"I hear there's gonna be a butler up there," one old guy wheezed to a mate the same night.

His friend replied, "I'd rather have a maid."

But the men's glee was tempered when they heard about three requirements the candidates had to meet. First, they had to be free of alcohol and drug abuse. Second, they had to appear mentally and emotionally stable. And third, they had to show a sincere desire to work.

That narrowed the field to about a score of men at Calvert, each of whom Friar Jack and his three Capuchin comrades interviewed during January and February in a first-floor office at the shelter.

Jack's colleagues were three very different sorts.

The wise one of the quartet was Roman Kozacheson, 51, a gray-haired priest with a trim white beard who came to Washington from York, Pa., where he was pastor of a white, middle-class parish. Stephen Carter, a chain-smoking 30-year-old, also came from York, where he used his fluency in Spanish to minister to Latinos. Christopher Jensen, a 33-year-old New Jersey native, was the only one who had not finished his studies for the priesthood. A hazel-eyed man with wavy black hair, he was known as a Capuchin brother and brought to the project still another point of view: he was a recovering alcoholic. 'Tired of the Cold'

Their interviews with McKenna House candidates were conducted by day when Calvert was virtually empty. With pencils and notebooks in hand, they collected names, dates of birth, work, criminal and military histories and other practical data.

"Do you have a problem with alcohol?" Brother Chris asked Robert Emil Moens during his interview.

"I am not and never have been an alcoholic," Moens replied, his grimy face lifted in dignity.

"How about drugs?"

"Never touch the stuff."

"Do you have any job skills?"

"I've done carpetry and upholstery work. I'd like to get back in it."

"Do you have any health problems?"

"Sometimes I don't hear so good. And my teeth, sometimes they hurt a lot."

"Do you have any medical insurance?"

"No," Moens said. "I don't even have any ID."

Brother Chris asked him why he was homeless.

"I broke up with the wife, she took the kids, and I lost my job," Moens said. "All that . . . I've found I can get by all right on my own. I'm doin' fine in my news shack, I guess. I got shelves, books, a carpet on the floor, Sterno. My identity's there . . . . "

He paused, puffing on a cigarette, and then continued. "The thing about being a bum is that you're practically invisible to the world. Nobody knows who you are and could care less. . . . All you do is survive day to day. . . . It's a time warp out there. If you want to, you can forget the past, the present and the future because none of it matters."

Brother Chris nodded, his pencil scribbling Moens' words. "What do you expect from McKenna House if you're accepted?" he asked.

"Well, I'd really like to settle down. I've been on the streets for two years now and I've made a lot of friends . . . but it's not something I want to do the rest of my life. I learned I can survive just about anything, but I want to do better than survive.

"I'm tired of the cold."

Brother Chris jotted it all down, and finished the interview by saying: "I think you could be a different person at McKenna House, Robert. You would probably find a sense of relaxation you haven't felt for quite a while. Do you think you could get used to that?"

"Sure," Moens replied. "I'd be grateful for the chance."

On Feb. 24 the four friars met for one last discussion. They were joined by a 30-year-old woman named Artice Forrister who had been hired as an employment counselor. Seated around an oval dining room table, they assessed the candidates for three hours and attempted to whittle about 25 names down to 15. After deciding on each name by a majority vote, they came up with a final list that was typed up on a sheet of stationery.

That night at Calvert, Moens raced through the hallways to find his best friend, Bryan Pleasant, 26, a sad-faced Lanham native with a fondness for chess, guitar-plucking and the show bars of 14th Street.

Through the musty traffic of derelicts and winos Moens ran, up the littered stairs, past the men playing checkers and cards, to a cold third-floor bunk room where he spotted his friend and grabbed him by the shoulders.

"Did ya hear?" he said, his green eyes sparkling with joy. "We're in, Bryan, we're in!

Monday: A promising start