Lin arrives late at her science class and is bewildered by the lever problem her teacher sets. 'Levers? Leavers are the only levers I'm interested in,' Lin says. 'As if I could be a scientist, as if I would be a scientist, there's no way.' Meanwhile, on the other side of the galaxy, the inhabitants of Zilch are searching for a logical, practical, problem-solving person, an engineer. Lin is off to the planet to be greeted with disdain. Earthlings can't be engineers. Needled by the aliens' lack of faith, she applies her practical understanding of levers to save them from disaster. Earthlings can do anything.