On July 2, 1996, an enormous mothership UFO that has one fourth the mass of the Moon, enters orbit around Earth, deploying assault fortress saucers, each with a fifteen-mile radius, that take positions over 36 of Earth's major cities. David Levinson, an MIT-trained satellite technician, decodes a signal embedded within global satellite transmissions, realizing it is the aliens' countdown timer for a coordinated attack. With help from his ex-wife, White House Communications Director Constance Spano, David, and his father Julius gain access to the Oval Office and warn President Thomas J. Whitmore of the attack. Whitmore immediately orders large-scale evacuations of New York City, Los Angeles, and Washington, D.C., but it is too late; the timer reaches zero, and the saucers fire destructive beams into the ground, causing massive walls of fire that kill millions. Whitmore, the Levinsons, and a few others narrowly escape aboard Air Force One as Washington is destroyed, along with the other locations over which the saucers are positioned.
