Kate lives in London, not far from the Thames. Next to the older sister, whom everyone admires, and the younger, whom everyone spoils, she feels a little out of place. Fortunately, he has a hobby of his own. She loves reading and decided to become a writer when she grows up. Every morning she invents new adventures and tells them to her best friend Olivia. But when he tries to write them down in the evening, he can't string a sentence together. One day, however, he discovers a mysterious diary covered in purple suede at a flea market.