(2001). Meet Dr. Hazel Barton and Nancy Aulenbach. These women are compelled to push their limits in hostile environments. They are cavers who risk fatal danger for the thrill of discovery. Barton and Aulenbach are extreme athletes and extreme scientists - scientists who gather their data in treacherous places where few dare to follow. In this documentary they travel to caves in Arizona, Greenland and Mexico searching for discoveries that may lead to cures for human disease.