Marcel is a French mouse, and a detective. One evening, at the Louvre museum, he sees a man steal a famous painting - the Mona Lisa. Marcel follows the thief to Venice and risks his life to get the painting back again.Marcel is a French mouse, and a detective. One evening, at the Louvre museum, he sees a man steal a famous painting   the Mona Lisa. Marcel follows the thief to Venice and risks his life to get the painting back again.