Theodore is a lonely man in the final stages of his divorce. When he's not working as a letter writer, his down time is spent playing video games and occasionally hanging out with friends. He decides to purchase the new OS1, which is advertised as the world's first artificially intelligent operating system, "It's not just an operating system, it's a consciousness," the ad states. Theodore quickly finds himself drawn in with Samantha, the voice behind his OS1. As they start spending time together...