Time Before Time begins with a genius professor (Emerson Whitmore) who is disgruntled with his mainstream scientist peers. His theories on many advanced civilizations developing on Earth over and over across millions of years got him crossways with most mainstream scientists and almost banned from institutions of higher learning. He decides to build a time machine to go see for himself what happened in history.

He hires a bodyguard, who is recently retired from the combined space and ground force of the Earth's defense service (John Chantry). Chantry is a big man and an expert in every weapon imaginable, a self-defense expert, and an expert in anti-gravity space combat. Together they make several stops and run into other races from other constellations that have tried to use the Earth for their own purposes.