An alien visitor warns that a family of asteroids are destined to destroy all life on Earth and encourages the earthlings to construct spaceships to save mankind. He is persuaded to take tens of thousands aboard his immense craft to improve the chances of survival of the species. But in the last scene, it is revealed that the alien’s mission wasn’t to save mankind but to restock his pantry.
Astronomer David Gannet’s pursuit of microbiologist Cora Martin is put on hold when Allen Becard, one of David’s grad students, discovers a spaceship traveling toward Earth and decelerating at a rate that suggests an Earth orbit. David hears the news aboard a space shuttle, where he is on a mission to repair the Hubble Telescope.
Reverend Qui Quetzal reveals his psychic vision of the approaching craft, which he points out is described in ancient scriptures, suggesting that this may be a return visit of unknown aliens.
Soon after it achieves Earth orbit, the craft, shrouded by a white sphere, “absorbs” the space shuttle with David and its crew.
General Ned Peregrine surreptitiously launches a pair of missiles at the spacecraft but they are swallowed up without exploding.
After weeks of quietly orbiting the planet, David communicates with President Victor Sanderling, stating that the shuttle crew, unharmed, is being sent home.
The tip of the bipyramid spacecraft detaches from the main vessel and descends to take up a position above the Washington Monument. A light beam emanates from this craft and the returning earthlings glide down the beam to the White House’s South Lawn.
David informs President Victor Sanderling that their alien host, Theo, wishes the President to invite world leaders to the White House so that he may deliver an important message.
At the meeting, Theo reveals that life-annihilating asteroids will arrive in 37 years and that the earthlings must begin building spacecraft so that enough people can escape the pending catastrophe and thereby allow humankind to survive.
He warns that…“to survive the eons of space travel, you must purge your seed of the greed, envy, lust, and inhumanity which so pervades you here on Earth. If you do not, you will be doomed before you are fulfilled.”
Theo allows thousands of fertile couples to board his craft… “Merely residing within the ark for a time can result in a cleansed soul…The offspring of these couples will become the first generation of earthling nomads.”
Theo offers technical help to the Earthlings and invites David to be his liaison to earth. He also invites Cora to join David on the spacecraft to nourish the child growing within her, conceived just days before when David and Cora were reunited at the White House for the shuttle crew debriefing. At first taken aback by this revelation, the couple finally agrees to the relocation.
After much entreating by the earthlings to allow thousands to remain on his ship when it departs, in the name of ensuring the survival of the species, Theo finally acquiesces.
But the earthling’s eagerness to “enrich the spaceship” prevents them from seeing that they are being hoodwinked. Theo is simply gathering fodder for the aliens.