Highly gifted 12-year-old Sue is a loner who is constantly teased by her classmates. As an ambitious scientist, her mother also has hardly any time for her. In her spare time, Sue escapes into daydreams about characters from her favourite superhero comics. One day, when she comes into contact with a mysterious liquid in her mother's laboratory, she becomes invisible. That's pretty cool at first, but proves to be really dangerous, because suddenly a lot of people are after her and the serum.