From the Game's Introduction:
Timmy and Sally are seven year old twin brother and sister. They live with their Aunt in a big house in the country. It has a big garden leading to small woodland and beyond that a small hill that is ideal for picnics on a sunny summer day. Timmy and Sally have a very vivid imagination though. To Timmy and Sally they don't live in a big house, no, they live in an old castle with the Ogre, the garden is a wonderland of adventure surrounded by the dark woods leading to the Scary Mountain where the monsters live.
Timmy and Sally have lots of scary adventures, and they get into a lot of trouble. Fortunately their imaginary friends are always there to help them.
Timmy & Sally's Imaginary Friends is a Role-Playing Game for a Story-Teller (or Games Master) and one or more players. It’s designed to be played as a short adventure with little planning, maybe in the back of a car on a long journey, or on a Sunday morning instead of watching cartoons. Well, okay, after the cartoons then.