Summary
Highlights
Two American astronomers, Marcus Wolf and Leo Biederman, discover a comet on a collision course with Earth. The government, led by President Tom Beck, initially keeps the discovery a secret to avoid mass panic and to allow time to develop a plan, which involves building a massive spacecraft called the Messiah to place nuclear devices on the comet and deflect its path.
The President announces the comet's existence and the plan to send a crew, including decorated astronaut Captain Spurgeon Tanner, to detonate nuclear bombs on the comet. He also introduces measures to freeze wages and prices, and outlines a contingency plan: underground 'arks' in Missouri to shelter a million selected individuals for two years in case the primary mission fails.
The Messiah spacecraft reaches the comet. The crew faces challenges, including treacherous terrain and equipment malfunctions while attempting to plant nuclear devices. During this dangerous operation, Gus Partenza is lost, and Oren Monash is injured. Captain Tanner takes command. The nuclear bombs are detonated, but instead of destroying the comet, it splits into two smaller, but still deadly, fragments.
President Beck announces the Messiah's failure and the splitting of the comet. He reveals that two fragments are still on a collision course with Earth. A subsequent missile attack using Titan missiles also fails to deflect the comets. The President then delivers a somber message, predicting a catastrophic tidal wave caused by the smaller comet (Biederman) impacting the Atlantic, and an extinction-level event from the larger comet (Wolf) hitting western Canada, plunging the Earth into a two-year dark period.
Onboard the damaged Messiah, Captain Tanner devises a desperate plan to destroy the larger comet. They decide to manually deliver the remaining nuclear bombs into a deep vent on the comet's surface, knowing this is a suicide mission due to lack of fuel for return. Emotional goodbyes are exchanged between the crew and their loved ones on Earth.
The smaller Biederman comet impacts off the coast of Cape Hatteras, causing a massive tsunami that devastates the Atlantic seaboard. Meanwhile, Captain Tanner and his crew successfully detonate the remaining bombs inside the larger Wolf comet, shattering it into harmless pieces. The film concludes with President Beck addressing the nation, acknowledging the immense loss of life and devastation, but offering a message of hope and resilience as humanity begins the long process of rebuilding.