George Vradenburg stands in front of 800 people and tells them they are going to die.

It’s April 21, 2005. Vradenburg’s audience, in tuxedos and evening gowns, fills the ballroom of the Grand Hyatt in downtown DC for the second annual gala of the Alzheimer’s Association. Vradenburg, an accomplished corporate lawyer who has just turned 62, is the gala cochair. He’s a tall man. Commanding.

He draws an imaginary line down the middle of the room. “Everyone on the right side, stand up,” he says. “Everyone on the other side, stay seated.” The two camps look at each other. “All of you standing will have Alzheimer’s disease by the age of 85. Those of you who are sitting will be taking care of them.”

The audience has heard the statistics before, but not presented so forcefully. They know that 5 million people in the United States have Alzheimer’s and that the number will multiply as the baby boomers age. They also know that the odds of developing Alzheimer’s doubles about every five years after age 65. That by the year 2050 the annual cost of caring for people with Alzheimer’s in the US will be more than $1 trillion, enough to overwhelm Medicare and Medicaid. They know that Alzheimer’s is the only major lethal disease for which there is no effective treatment, prevention, or cure.

Yet those who are standing up might live longer with Alzheimer’s than those who spend their life feeding, lifting, and diapering a sick loved one. Look at the person pushing the wheelchair, caretakers say. That’s who dies first.

Vradenburg is an appropriately solemn messenger for such grim news. His wife, Trish, the blond woman in the red dress standing next to him, the former sitcom writer—she’s the funny one. He leads with the hard truth; she softens it with a well-timed line. “People ask me, ‘Who wants to live to 85 anyway?’ ” she’ll say. “Eighty-four-year-olds!”

Trish Vradenburg, now 66, hopes to be so lucky. Her dream is to die after getting hit by a truck, with just enough time to eat a frozen Snickers bar before she goes. But she’ll settle for any ending other than the one she’s imagined for the last two decades. The one she feels trickling down her bloodline.

As the Vradenburgs stare through spotlights into a ballroom full of people, half of them standing, half sitting, they know they might as well be looking in a mirror. They know these odds. And they know they aren’t good.

It was 1988. Trish and George Vradenburg were asleep in their home in South Orange, New Jersey, a few miles from Trish’s mother, Beatrice Lerner. At 3 am, the phone rang. “There’s a strange man here,” Lerner said. “He’s trying to rob me.”

The drive took five minutes. George and Trish found Lerner’s windows closed. Her door hadn’t been forced open, but she was on guard. She pulled her daughter and son-in-law aside and whispered, “That’s him. Who is he?” Lerner was pointing at her husband, Joseph.

After that night, she became more paranoid. And forgetful. And quickly she, too, became unrecognizable.

One day Trish took a bad fall and called her mother to take her to the hospital. The normally hypochondriacal Lerner—whom Trish could have imagined driving the ambulance herself, all the while terrifying her daughter with prognoses of infections and bone disease—arrived half an hour later.

“Mom, we have to get to the hospital!” Trish said.

“All right,” her mother said casually. “Do you think they’ll have tea there? How do you like my hat?”

Lerner had been among the most influential Democrats in New Jersey. In photos lining a wall in George and Trish’s house, she stands alongside John F. Kennedy, Harry Truman, Adlai Stevenson, Frank Lautenberg, Bill Bradley, Jimmy Carter. In many of those photos, she’s the only woman. A woman who once was on a list of Nixon White House enemies to be investigated by the IRS.

Eventually Lerner forgot her own story. Her brain filled with a normally beneficial protein that, in abundance, clumped in the space between brain cells. The hardened plaque blocked transmissions among synapses, the pathways the cells use to send commands that control the body, memory, the senses. With the brain’s communications system jammed, a second wave of attack arrived. Another protein, what scientists sometimes call “the executioner,” burrowed into the weakened cells, destroying them from the inside. Cell by dying cell, her brain shut down.

As the proteins flooded Lerner’s brain, her body went rigid. She withered, immobile, in a New Jersey nursing home. By the time she died in 1992, she’d been so long removed from the world that no one from her storied political past remembered her anymore.

Watching her mother’s descent scared Trish. And watching it scare Trish—seeing her wonder every time she misplaced her keys or her cell phone—scared George. How many times can someone forget something until the problem isn’t just forgetfulness?

George knows the disease isn’t just in Trish’s blood. It’s a constant presence in her thoughts and in her sleep. She dreams about her mother all the time.

The 2005 gala is supposed to be about triumph over that fear, measured in the money George and Trish will raise—more than $1 million—and in the personal affirmations the speakers will share. But Washington galas blend into one another in a season crowded with fundraisers for diseases. So when George goes off the usual script and puts the cold reality of the numbers right in the center of the room, his words unnerve people.

What no one knows yet on this night, not even George and Trish, is that the Vradenburgs are about to start a movement. It will be fueled by their fears and by an audacious goal: They plan to find a treatment or a cure for Alzheimer’s in their lifetime.