More than anything in the world, Rosalie, the owner of a tiny postcard shop in the center of Paris, loved the color blue... But she could not even imagine that one day, together with a venerable French writer, whose books she had been reading since childhood, as well as young and a very nice American professor, she will find herself in a completely incredible story and the color blue will play such an important role in it. And even more so, she could not imagine that this story - and the secret hidden in it - would completely turn her life around and make her the happiest girl in the world. However, “spring sometimes fulfills promises that winter did not keep”...