During one of her guided tours at Le Louvre, Cécile sees in the museum galleries a small white kitten who seems to be listening to her commentary. When she tells her colleague, he doesn't believe her. Monsieur Marcel has been a night time security guard for years. His family has worked at Le Louvre for generations. That night, he is training Patrick, a young recruit. Very quickly, Monsieur Marcel strays from the usual path to get to the attic. There, Patrick discovers cats. Marcel feeds them and explains to his young colleague that these cats have always inhabited Le Louvre. They were already there when Le Louvre was still a castle. Once the two guards have left, the cats start to speak. There is Blue-Beard, Myosotis, Sawtooth, and the small white cat is Snowflake. They say he is special, they say he can enter the worlds of paintings...