A young girl takes it upon herself to stop a vicious rumor about her new best friend in the comedy Sally Marshall Is Not An Alien. Pip (Helen Neville) is a 12-year-old girl living with her family in Adelaide who isn't like the other kids she knows -- she's smart, serious and likes to watch the skies with her prized telescope. She's also a bit shy and doesn't know what to do about Ben (Glenn McMillian), a neighborhood boy who seems to like her. Rhonnie (Thea Gumbert), a mean-spirited girl in the neighborhood, doesn't much like Pip and doesn't care who knows it. However, Rhonnie discovers someone who bothers her even more when Sally Marshall (Natalie Vansier) moves into town. Sally wears dark glasses, reads grown-up books, likes to hang upside down and doesn't have an Australian accent. Sally is obviously not from around these parts, and Rhonnie is convinced this means Sally is a visitor from outer space. Pip finds this ridiculous and accepts a challenge from Rhonnie -- either prove conclusively that Sally isn't a space alien, or lose her telescope.