'A small girl, Sarah opens her front door and sees a huge, steep slope leading upwards, as if into the sky. She wants to visit her friends but the slope blocks her. Literally an insurmountable problem that she unsuccessfully tries to solve. In desperation, she calls in a slope doctor. He is not much help but gives her some cards to fill in that he then posts off to her friends who live beyond the giant slope and they soon come for a visit.' (introduction)