In the series' pilot episode, an enormous ball of light deposits a group of exactly 4400 people in the Cascade Range foothills near Mount Rainier, Washington, United States. Each of the 4400 had disappeared in a beam of white light at various times starting in 1946. None of the 4400 have aged from the time of their disappearance. Confused and disoriented, they remember nothing between the time of their disappearance and their return.