The earth will be hit by an asteroid, and the end of the world is three weeks away. People spend the last days in their own way. Some are busy breaking up, some are busy accompanying their families, and some are busy fulfilling their wishes. Doug (Steve Carell)'s wife ran away the first time, leaving him bored. He happened to meet his female neighbor Penny (Keira Knightley) crying under the window because she missed her flight home, and the two got to know each other. Penny returned many letters that were delivered to his house by mistake to Doug. Doug found that there were letters from his first love a few months ago. Penny felt very guilty and decided to help Doug rush to see his first love. The two drove on the road and got along very well all the way until they found that when the end of the world comes, the people they want to be with are each other...