The Secret World of Og is a children's adventure about three young girls who venture into an underground cavern beneath their playhouse to look for their lost baby brother. There, they discover a land of little green people who are enamored by the world above but won't allow anyone to leave their cavern for fear they might "tell".

Michael Long, an undercover police officer, is shot while investigating a case and left for dead by his assailants. He is rescued by Wilton Knight, a wealthy, dying millionaire and inventor who arranges life-saving surgery, including a new face and a new identity--that of Michael Knight. Michael is then given a special computerized and indestructible car called the Knight Industries Two Thousand (nicknamed KITT), and a mission: apprehend criminals who are beyond the reach of the law. The series depicts Michael's exploits as he and KITT battle the forces of evil on behalf of the Foundation for Law and Government.