Billy is a Bit - a tiny element in the Memory Component of a home Computer - and he's bored, very bored.
His whole life consists of standing up and sitting down on demand without ever understanding why. So one day, when the officious Barry, the Parity Bit of Billy's section, orders him to sit down, he doesn't. He crouches. Utter confusion ensues: Billy is IN-DE-TERMINATE, and that means that the whole System - the Computer in which Billy lives - cannot function properly. Perhaps Billy's job is more important than he ever imagined.