The teenage siblings began punching Brittney. Fighting for her life, she kicked and bit her attackers as she desperately tried to protect her sister. While Beau stabbed tiny Kristyanna with a large kitchen knife, Monique stabbed Brittney 27 times -- in her arms, chest, back and legs.
Beau and Monique ran from the blood-soaked trailer into their getaway car, and Brittney was unable to move.
"I looked over at my sister and I could hear like gurgling. ... I didn't at the time know what it was," she said. "And then I tried to get over there and I couldn't really move, so I started screaming help, help, help."
Tamara Bergeron returned to her trailer and also began screaming. Brittney says she remembers her mom holding towels and rags over her wounds to stop the bleeding.
A neighbor called casino security, who called the police.
"Brittney was lying in a puddle of blood and just, just screaming," said Bradley Swanson, the first officer to arrive at the scene. Brittney looked Swanson in the eye and told him she didn't want to die.
The two girls were flown to the Trauma Center at University Medical Center in Las Vegas and rushed into surgery.
Kristyanna had been stabbed repeatedly in the head and neck. The knife had pierced her skull and brain, and multiple wounds marked her 32-pound body. Kristyanna never made it out alive.
Brittney was in the operating room for two hours. When she awoke from her surgery, she learned that one of the knife wounds had severed her spinal cord and that she would never walk again.
"And then I woke up in the hospital and I had a tube down my nose and staples and, everywhere, and I had a cast on my arm and there were cards all over my room."
Meanwhile, Beau and Monique Maestas stole their grandmother's Honda and headed north on I-15 to Utah. Police issued an alert, and within five hours the pair were arrested in Nephi, Utah. Beau Maestas confessed immediately. He tried to protect his little sister and claimed she had no role in the attack. But it soon became clear that 16-year-old Monique Maestas was the one who'd stabbed Brittney.
More than three years after the crime, the Maestas siblings each pleaded guilty to murder. Beau Maestas was sentenced to death but his case is under appeal, and his sister received life in prison; she won't be eligible for parole until she is 65.
In the years that followed, Brittney underwent hundreds of hours of counseling and physical therapy, without her sister by her side.
"It was hard," she said. "It was weird, because I didn't have her there and sitting there, you know, always laughing with me. ... She always followed me and wanted to do everything I wanted to do."
Still missing her sister, Kristyanna, Brittney adjusted to life as a paraplegic.
Brittney now needed special care and parents who could take care of her and meet all her medical needs. That's when one of Nevada's award-winning foster care parents stepped in.
Judy and Bill Himel have fostered more than 30 medically fragile children, including infants and children with severe problems and no place to go.
The electrician and housewife had seen a news report about Brittney and knew they would be getting a call from the Department of Family Services asking if they would take her. A few days later, Brittney had a new home.