In the series' pilot (also known as "Code Name: Minus One"), a government undersea salvage operation is blown up, trapping an agent in the explosion. But a chemical reaction has given the man the ability to render himself invisible. The agent attempts to use this capability to discover who was responsible for the sabotage
Sam is assigned to drive a truck transporting a secret fuel additive that can triple fuel economy in cars, along with the man who developed it. Unfortunately, the additive is unstable and explosive and the scientist has sold out and is trying to eliminate Sam and the evidence
After a scientist is fired for building a doomsday machine, he uses the robot against the government in a blackmail plan
A group of spies infiltrates Intersect with a double of Sam, so he turns the tables by taking the imposter's place in the group
A scientist for a government research project is dead, and Sam must find the old man's secretary in hopes of learning how to complete the project
Sam is being hunted for the apparent murder of an Intersect agent, and there is video tape to prove it. Only Sam doesn't remember doing it and while on the run, attempts to clear his name.
Casey's attempt to help a noted female scientist defect from an Iron Curtain country is hampered by the woman's daughter, whose attachment to a double-crosser jeopardizes the trio's escape.
Leonard Driscoll summons Sam Casey to unmask Robert Denby who he suspects of sabotaging the U.S. defense system
A crew turns mutinous and takes captive a shipping magnate as their hostage
Top boxer Arch Kingston left the business following the death of his brother in the ring. But he decides to come back one last time for promoter Harry Trent, only he doesn't trust Trent and asks Sam to use his ability in the ring to keep things honest
Sam is assigned to protect and help a deposed African leader known as The Lion return to his country in order to end the ongoing civil war. During the journey both men's personalities are drawn, and Casey imbues The Lion with ideas about the sociological reality of his people.
Pretending to be a rookie, Sam teams with a veteran supposedly involved in an assassination plot
Two episodes ("Smithereens" and the unaired "Buffalo Bill Rides Again") were re-edited into one 90-minute TV movie titled "Riding With Death," which was released in 1981. This film used scenes from "Colossus: The Forbin Project" as establishing shots for sweeping computer room scenes. The film dealt clumsily with the dropping of Katherine Crawford from the cast by the latter episode, the length of time between filming (William Sylvester had grown a thick bushy mustache in the interim), and the appearance of an arch-villain in the second "half" who did not exist in the opening of the series (save for a clumsy overdub referring to the villain's elusiveness in the final minutes of the first segment). Both parts feature singer Jim Stafford as a trucker named "Buffalo Bill" who befriends and helps Sam.