Nastasha was born and raised in Prypiat, Ukraine, and was 10 years old when she and her family were exposed to radiation due to the Chernobyl nuclear accident, on April 26, 1986. In 1990, Nastasha's parents were killed when they were exposed to lethal amounts of radiation while helping in the clean-up. This made her become very strongly opposed to nuclear weapons and nuclear power, claiming that nuclear bombing represents "an invisible war that transcends borders and generations." She later moved to the United States when her parents died, still plagued by the effects of residual radiation poisoning and the gauntlet of procedures it entails. However, because she had never been diagnosed with cancer, the help she had been able to receive was limited. Nastasha joined the DIA (Defense Intelligence Agency) in 1992, then at the NSA (National Security Agency), regularly dealing with top-secret information. While in the DIA, she met and later married Richard Ames, but the marriage didn't last long and they quickly divorced. In her own words they "spent much of [their] brief marriage in disagreement over virtually every issue," remaining single from then on. The end of the Cold War saw her join the ranks of displaced military analysts. She then wrote freelance military criticism for a variety of military intelligence journals including the U.S. Naval Journal. In 1996, Nastasha attended the Canberra Commission, the world's first nationally hosted nuclear weapon abolition proposal committee. She participated in the Commission as an advisor. Afterwards, she joined NEST (Nuclear Emergency Search Team) as a military and nuclear analyst. During this time, she went to live in Los Angeles. Nastasha had a friend who became affected by PTSD, due to the trauma of having to fight against his fellow citizens in Chechnya, and committed suicide six months after his return.
In early 2005, Ames made contact with Nastasha and forced her to help with an anti-terrorist operation, being conducted by Solid Snake on Shadow Moses Island. Her LA home was converted into a makeshift command center for DOD personnel, with Nastasha providing radio support to Snake as he infiltrated a nuclear weapons disposal facility. Since Snake was an amateur when it came to nukes, Nastasha kept him informed of the latest news on nuclear weapons development and military affairs. Ames kept many secrets from Nastasha during the operation, though she came to learn of various classified government projects and conspiracies, including the Patriots' existence. Some of the information she uncovered was so top secret that she began to wonder if she would even be allowed to live once Snake's mission had been accomplished. After the terrorists were thwarted by Snake, Ames handed Nastasha a disc containing data on the Pentagon's FOXDIE virus, hoping that she could use it as leverage to keep herself safe. Ames disappeared from her life shortly thereafter.
Afterwards, Nastasha fled from her home in California and went into hiding. She felt incredibly affected by what she had heard during her time helping Snake. After failing to contact Ames through the DIA, Nastasha was convinced that buying her safety and freedom had been a costly act for him. Having grown tired of being an objective bystander, she decided to go public with what she knew and attempt to expose the conspiracy behind the incident. Putting herself in renewed danger, she wrote a book entitled "In the Darkness of Shadow Moses: The Unofficial Truth". After overcoming many obstructions, Nastasha was ultimately successful in publishing her book. She donated the royalties to help fund Snake and Otacon's anti-Metal Gear organization Philanthropy. Afterwards, she disappeared from the public eye once more, with even Snake being unaware of her location by the time of the Big Shell Incident in 2009, though he assumed she was still a heavy smoker.