 Kate Forster (Sandra Bullock) is moving out from her lake house, built all of it with glass. She is a doctor and has just begin to work in a hospital in Chicago, moving to a new flat in the center of the city. Alex Wyler (Keanu Reeves) is the new owner of the lake house, a young architect who s working in the construction of a new complex of houses at the city skirts. Alex and Kate are maintaining a correspondence, talking about the house matters, sending each other letters, which are put in the lake house s letter box. But a strange thing is happening, because both of them find out that the letter box is working as a kind of time communication channel, between the year 2004, where Alex s living, and 2006, the year that Kate s actually living. After sending each other many letters talking about their lives, and Kate talking to Alex about how life will be in two years, it seems like they re falling in love each other. But maybe they will never meet each other, because of the time distance. Nevertheless, Kate comes up with a memory from 2004, when she forgot a book in a train station, Jane Austen s "Persuasion", and she ll ask Alex to go to that place in that precise moment, when she lost the book. Maybe the future of Kate is about to change, when Alex decides to meet Kate s other self in the past, despite the fact that she has a boyfriend. They will learn that playing with time could be a little bit dangerous for both of them, but Alex will take everything into his hands to finally meet Kate in the future.