Jet Propulsion lives with his family from the fictional planet, Bortron 7. They live on Earth where they study human customs and Earth environments for a travel guide. Jet has made friends with neighborhood kids, including Sean, Mindy and Sydney, whose parents work at the nearby Jet Propulsion Laboratory. Their car turns into a rocket-ship with which they frequently take the older kids into space. Their alien identities are known to Sean, Mindy and Sydney, but they otherwise make some effort to conceal their origin.