Set in the near future (specific year unnamed), Theodore is a sad sack. His marriage just broke up, he does not want to go out or do things, like hang out with friends, and his day job is writing personal letters (love letters, thank you letters, etc.) for other people who are just as pathetic as he is. So, what does he do to try to change things up some in his life: he buys a new computer with a personal, talking, interactive, emotive operating system (OS). And this OS changes his life.