Humanity lives in fear of an alien invasion: for the first time in history, a coded message from outer space has reached planet Earth. A few months later, the 12,000 residents of Sepulveda vanish. Authorities immediately quarantine the area, a free zone where drug trafficking and illicit sex were the most common businesses. When strange magnetic phenomena are observed, military authorities grudgingly concede the possibility of an alien offensive, and send professor Larsen -a renowned astrophysicist specialized in UFOs- to lead a quick investigation in the ghost town.