After astronomer Zane Zaminski (Charlie Sheen) discovers a radio transmission that originated from space, he tells his boss, Phil (Ron Silver), who ignores him. Zane is promptly fired, and decides to investigate the signal himself. When he discovers a return radio transmission from Mexico, he goes to explore. There he meets climate scientist Ilana Green (Lindsay Crouse), who is studying anomalies in gases in the area. Zane soon makes a shocking finding that puts him in great danger.