"Demain" is a French novel that tells the story of two individuals who meet through the internet and decide to meet in person at a restaurant in Manhattan. The main character, a 32-year-old woman, is still searching for the man of her life while the other character, a widower, is raising his young daughter alone after losing his wife in a tragic accident. As they get to know each other better, they discover that they have more in common than they initially thought and start developing feelings for one another. The book explores themes of love, loss, and the power of human connection in overcoming life's challenges.