Ryza is an ordinary girl. Tired of boring village life, she escapes the village to gather with her good friends in a secret location to talk of their dreams and plan thrilling adventures. One day, the determined Ryza and company decide to head for the forbidden "island across the shore" as their first exploration trip. Together with the alchemist and other friends they meet there, they have a "summer adventure" that they will never forget.

Paris, 1830. In the heart of the town, Vidocq, a famous detective, disappears as he fights the Alchemist, an assassin that he has been pursuing for a few months. His young biographer, Etienne Boisset, decides to avenge Vidocq's death and takes the investigation on...