The SAs a girl, she tried to break the color barrier in Houston schools. As an adult, she worked in the African liberation movement and against apartheid.

Marion Williams built the house on Farmer Street himself, board by board, nearly 50 years ago. That was long before the concrete river of the East Freeway inundated dozens of square blocks of nearby homes, starting the long, slow decline of the Fifth Ward.

It was from the Farmer Street house on a hot September morning in 1956 that Williams walked his 14-year-old daughter Beneva into an unwelcoming world -- a world in which African-Americans were forbidden to drink from the same water fountains or attend the same schools or even die in the same hospitals and be buried in the same graveyards as white people. It was a world that young Beneva Williams was sent to change, although at the time she barely comprehended the significance of her assignment.

Thirty-nine years later, Beneva Williams Nyamu is back at the still trim two-bedroom home on Farmer Street, sitting on the living room couch and reviewing a lifetime of change that has taken her on a tumultuous odyssey from the Fifth Ward to Mother Africa and back to the Fifth Ward. A small woman with lively eyes and short-cropped hair, she impatiently thumbs through photo albums spread on a coffee table. The plastic-sheathed pages are studded with empty squares, the attrition of years of family picking and pilfering and forgetfulness. It's the beginning of the Memorial Day weekend, and Beneva's mother, Ada, has sequestered herself in the kitchen baking dinner rolls and shepherding short ribs through an oven purgatory toward a higher purpose. In a backroom, 100-year-old Dock Hardison, Beneva's maternal grandfather, sits quietly in a chair next to a bed, his tiny frame birdlike and vulnerable. He smiles but barely mumbles.

It might be an idyllic gathering of the generations on a holiday weekend to celebrate family and long life. It isn't. It is quite possible that the 53-year-old Nyamu will not outlive her grandfather. The tension in the small house is palpable.

For Ada Williams, the kitchen work provides a refuge from the painful issues -- some reverberating from the deep past and others from the all-too-real present -- that are being dredged up as her daughter recounts her eventful life to a visitor. Ada remembers well the morning that her steelworker husband walked Beneva the few blocks to then all-white McReynolds Junior High and helped fire the first shot in the decades-long battle to desegregate the Houston Independent School District. Beneva and Delores Ross, another young girl who tried to enroll at an all-white elementary school, never studied in an integrated grade school classroom. But theirs were the names on an NAACP lawsuit that eventually pried opened HISD's doors to thousands of other African-American youngsters.

Ada, who worked as a seamstress then, also remembers well what happened after the suit was filed -- the phone ringing at the house on Farmer Street for weeks and the anonymous voices issuing threats and racial epithets. Ada never said a word, listening quietly in the dark as the invective spewed from the mouthpiece. She tried, she says, to insulate her daughter from having to live with that fear.

"I never knew that," says Beneva, listening to her mother talk of the past in the bright, innocuous light of a Saturday morning in 1995.

It is to this house and city Beneva has returned, unwillingly, a prisoner brought back to Houston from Zambia nearly five years ago after the next chapter in her life on the African continent was aborted, possibly by the prick of a needle in an apartment rug. The sliver festered, and Beneva made a choice she now says she instinctively knew was wrong from the moment it was made, granting her approval for a minor surgical procedure to remove the needle in a ramshackle Lusaka hospital. Then followed respiratory problems that in retrospect probably were the initial signals of HIV infection. It is also possible, Nyamu acknowledges, that the operation simply triggered a latent HIV presence acquired through relations with a boyfriend in past years. In a Third World country not far from the epicenter of the 20th-century's worst epidemic, there are many possibilities for infection.

It was in Houston on a visit to see her family in 1989 before heading to Namibia to work with the new government that she was tested by a doctor and told she was HIV-positive.

Beneva's mother found the news of the virus harder to deal with than the racial contagion she faced down nearly four decades ago.

"It cuts you in two," Ada Williams says of her daughter's illness. "It's something you have to live with, but it's hard."

Beneva says her mother has come to accept the reality of the disease, but, nonetheless, Ada has decreed her kitchen off-limits to her daughter.

"I don't have to wash dishes anymore," Beneva explains.

"Come up and visit me at Park Plaza," commanded the message on the recorder phone. "I'm going to be there for a week and I sure don't want to go all that time without a visitor."

The premise seemed improbable. This reporter has known Nyamu for nearly 20 years, and "alone" is the one word that never would have been applied to her situation. Friends in Tanzania remember that while her African husband was quiet and clannish, Beneva epitomized gregariousness and rarely could be found at home alone. In 1975, Nyamu became the supervisor of a Harris County child welfare unit, and her in-your-face, get-with-my-program style was like a cup of strong black coffee. Some were energized by it, and some people were driven up the wall by it. With a manner friends call feisty and she terms "assertive," Beneva has stimulated plenty of both reactions in her life, most recently when she was fired from SHAPE Community Center in the Third Ward after a run-in with longtime director DeLoyd Parker. She's a perfectionist who has little patience for the time required to gradually bring people around to her point of view.