Zinca, Axel, Oto, Helena, Ciro and Aristide the fox want to be the best detectives in the world. They are studying in the first year at the famous Avante school, where they can demonstrate their skills as investigators. Together they make up Nautilus, a group with a shared passion: solving mysteries.
For the first time ever, the seven most valuable precious stones in the world are on show at Billinghurst Castle. One by on they are mysteriously disappearing.
The kids from Avante begin their detective work surrounded by ornithopters and automatons, but the case gets complicated when the head of security prohibits them from entering the castle. Will they discover the robber beafore the last stone disappears?
