In 1947 New Mexico, a radio operator receives a bizarre signal, coming from Roswell. He decides to investigate the signal's origin and goes out to follow it, never to be seen again. Present day and the same signal is received from the South Pole and then retransmitted from the Falkland Islands to the United States. A satellite image captures an unknown object sitting on the Antarctic snow. Cryptologist Julian Rome (James Spader), a teacher at the University of California, Berkeley, is invited to investigate the mystery. He is sent to an Antarctic research base, which includes a huge greenhouse of genetically modified plants being studied by the scientists. They find what appears to be an alien vehicle frozen in a huge block of ice. The unknown object is shaped like a shell or pod and is emitting the mysterious encrypted signal. Once it is freed of the ice, Julian discovers that it has a powerful static electric charge on its surface and painfully shocks anyone who touches it.
Julian tries to decrypt the signal (which soon proves to be: "Do not open!"), while another team works to open the alien shell. They succeed in cutting off the lid, which allows a viscous alien liquid to pour out. An alien also escapes and at the same time an airborne virus sealed in the shell kills four members of the scientific team by melting them from within. The virus also kills all the plants, making them wilt and turn brown. The virus has an unusually high speed of transmission and extreme virulence. It kills anyone within a few minutes of exposure.
The government is aware of the alien virus and the global risk that it poses. They ask a Russian nuclear submarine to fire a nuclear missile at the base before the threat can spread. As the submarine nears its firing position, Julien manages to communicate with the alien, before it is unfortunately killed by one of the survivors. Julian realizes that if any of the survivors leave the base alive, the lethal alien virus will cause a pandemic destroying all life on earth. Just a few seconds before the missile hits, he and three others, Shelly, Kate, and Dr. Gierach, are rescued from the base by an alien spacecraft (which had homed in on the same signal Julian was studying).
In the aftermath, the government mounts a cover-up campaign by claiming that an experimental nuclear reactor at the base went into melt-down, destroying all of the facilities and killing everyone. The film ends with the alien spacecraft, still carrying the human survivors, leaving the solar system.
Who manages to communicate with the alien?
Julien