"The Doomsday" depicts a science fiction story in which the Earth, represented by the United States, suddenly cooled down sharply within one day and entered an ice age. In the story, climatologist Jack Hall (played by Dennis Quaid) pointed out after observing prehistoric climate research that global warming caused by the greenhouse effect will cause unprecedented disasters on the Earth. Dr. Jack warned government officials to take preventive actions, but the warning was obviously too late. Dr. Jack Hall then urgently told the US Vice President to announce that all Americans south of 30 degrees north latitude should evacuate to the equator as soon as possible, and people north of the line should try to keep warm. At this time, Dr. Hall learned that his son Sam (played by Jack Gyllenhaal) went to New York alone to rescue his girlfriend, so he decided to take the risk and go to New York to launch a rescue operation in the ice and snow. At this time, the disaster began in New York, and the skyscrapers in Manhattan were hit by a strong cyclone and most of them were destroyed. Suddenly, a violent and turbulent flood gushed out of the subway tunnel. The flood swallowed New York, submerged the United States, and Europe ceased to exist under the flood. Since then, ice and snow covered the entire surface of the earth, and the ice age began.