Katie's grandma has lost her glasses and she can't see a thing without them. While Katie and gran are in the garden searching for the specs, they come across a cat. A very big cat. The big cat moves in with them. He might be good fun, but he takes up lots of space and eats every scrap of food. Eventually the cat's mum and dad turn up, looking for their missing son. And they just happen to have found gran's glasses too. The tiger family are delighted to be reunited ¿ and gran now sees that she's been sharing her house with... a tiger!