Zane Zaminski, portrayed by Charlie Sheen, is a radio astronomer working for SETI who makes a groundbreaking discovery: an extraterrestrial radio signal emanating from Wolf 336, a star located 14 light years away from Earth. Eager to share his findings, he reports to his supervisor, Phil Gordian, but his claims are met with skepticism and outright dismissal. Facing unforeseen consequences, Zane is fired due to alleged budget cuts and promptly blacklisted, which effectively bars him from employment at other telescopes.
To make ends meet, Zane takes a position as a television satellite installer, cleverly repurposing his customers' satellite dishes into a makeshift telescope array. With assistance from his young neighbor, Kiki, he continues his clandestine work from his attic. Zane’s efforts lead him to successfully relocate the alien signal; however, it becomes drowned out by a terrestrial frequency from a Mexican radio station. In his quest to share this vital information with his former colleague, Calvin, Zane is devastated to learn of Calvin's untimely and suspicious death from carbon monoxide poisoning.
Determined to uncover the truth, Zane travels to Mexico, only to find that the radio station has been reduced to ashes. His investigation directs him to a nearby power plant, where he encounters Ilana Green, a climatologist who is battling to preserve her atmospheric analysis instruments against the plant's aggressive security. During their time together, Ilana reveals alarming data indicating that the Earth's temperature has spiked several degrees, resulting in the melting of polar ice caps, and she suspects the power plant might be responsible.
After a precarious escape, Zane learns a shocking revelation: one of the guards bears a striking resemblance to Phil, albeit of Mexican descent. As Zane and Ilana conspire to delve deeper into the power plant’s operations, a perilous situation unfolds when an alien device is secretly released into Zane's attic, creating a miniature black hole that obliterates all his equipment. Tragically, Ilana meets her demise at the hands of a deadly scorpion placed in her room.
Zane discovers that the power plant serves as a facade for an underground alien base, where extraterrestrial beings possess the ability to disguise themselves and infiltrate society. These aliens have been clandestinely releasing harmful emissions into the atmosphere, endangering Earth's environment. During a tense encounter, Zane is pursued by alien agents but manages to escape back to town, only to find himself implicated in Ilana's death once her lifeless body is brought to the local sheriff's station. Fleeing once more, he returns to the United States and confronts Phil at the Jet Propulsion Laboratory, compelling him to confess the alien agenda: they intend to render Earth uninhabitable for humans while making it suitable for themselves.
Effectively capturing the conversation on tape, Zane realizes his only avenue to expose the truth is to broadcast the recording. With the support of his girlfriend, Char, and Kiki, he races to a nearby telescope to transmit the tape globally. However, Phil's agents thwart their plans by disabling the telescope controls. Entrusting Kiki with the responsibility to transmit the tape at the right moment, Zane and Char barricade themselves in the control room. As Zane orchestrates the adjustments, an unforeseen twist occurs when Kiki reveals himself as an alien agent, permitting Phil into the room to seize the tape.
In a wild scramble, Zane utilizes cryogenic gases to freeze Phil and his agents, and in the ensuing chaos, a sphere is dropped, spawning another singularity within the control room. Zane and Char narrowly escape through the telescope’s optical path just before the device implodes the majority of the facility. As they emerge onto the collapsed dish, they catch sight of Kiki once more. Zane defiantly informs Kiki to relay his message to the aliens, pledging to broadcast the incriminating tape. The film concludes with Zane's crucial conversation with Phil being broadcasted worldwide, solidifying his commitment to reveal the alien threat to humanity.
