In Grandma's house there's a catflap, with some very strange symbols drawn on it. and it's much bigger than normal. But what's really strange is that Grandma doesn't have a cat. Marina, Lucas and Zoe discover that the catflap leads to a world of fantasy where they have a mission, they must save the king of the forest. Impulsive mermaids, greedy dwarves, dragons that look like lizards. This is a mission for the magic rescuers!