Geronimo Stilton : Cavemice - Help, I'm In Hot Lava! (#3)

Geronimo Stiltonoot and his family are off to find a cure for Grandma Ratrock's aches and pains. She's heard that a remedy hides in a legendary lost valley. Geronimo isn't sure it exists, and thinks they'll be home in no time. Little does he know they'll end up on an adventure among geysers, volcanoes, and rivers of molten lava!