影片主要讲述在2012年，人类被某种病毒感染，作为军方研究病毒的科学家罗伯·奈佛（Robert Neville），因为他体内有免疫力，所以他成了纽约城内的幸存者。白天他带着一只名叫Sam的狗在各个街道上寻找食物，并且用广播呼叫，看看是否有其他的幸存者，晚上，因为感染这种病毒的人们，并没有真正的死亡，而是成为了夜魔，在夜晚出来发出攻击，罗伯·奈佛无奈只能躲在屋子里

后来狗狗Sam感染了这种病毒死亡后，罗伯·奈佛感到无比的寂寞，想要和这些夜魔同归于尽，就在这时，另一个幸存者Anna解救了他，但是两人出现了矛盾，不愿一起，Anna认为山上还有幸存者，她想要去寻找，但是罗伯·奈佛却坚持守在纽约。

罗伯·奈佛一直坚持在实验室里研究治愈这种病毒的方法，直到有一个夜晚夜魔来到了罗伯·奈佛的藏身之处，经意外发现罗伯·奈佛的实验成功了，只要坚持到天亮，人类就有救了。

The film mainly tells that in 2012, human beings were infected by a certain virus. As a military scientist who studies viruses, Robert Neville, Because of his immunity, he became a survivor in New York City. During the day, he took a dog named Sam to search for food on various streets, and used the radio to call to see if there were other survivors. At night, because people infected with this virus did not really die, but Became a night devil, coming out to attack at night, Rob Knife had no choice but to hide in the house

After the dog Sam was infected with the virus and died, Rob Nefer felt extremely lonely and wanted to be with these nights At this moment, another survivor, Anna, rescued him, but the two had conflicts and refused to be together. Anna believed that there were survivors on the mountain, and she wanted to find them, but Rob Nefer insisted. Stay in New York.

Rob Nefer has been insisting on researching a cure for this virus in the laboratory, until one night the night devil came The hiding place of Rob Nefer was discovered by accident. Rob Nefer's experiment was successful. As long as we persist until dawn, human beings will be saved.