Geronimo Stilton Cavemice: Surfing for Secrets (released 6/30/15) Geronimo Stilton's ancient ancestor is back in another prehistoric adventure! A mysterious rodent has been shipwrecked on Mouse Island. He's a prehistoric pirate, and he's searching for a lost Stone Age treasure! Geronimo Stiltonoot and his family volunteer to help him on his dangerous hunt. Petrified cheese! Can they find the treasure without going extinct on the way?