The sudden death of a top-level government scientist embroils his unsuspecting former secretary in a race against time between Sam Casey and foreign interests seeking top-secret data about her former employer's work.

Two episodes, "Smithereens" and the unaired "Buffalo Bill Rides Again", were re-edited into one ninety-minute television movie titled Riding With Death, which was released in 1981.

Riding with Death used scenes from Colossus: The Forbin Project as establishing shots for sweeping computer room scenes. The "Guardian" logo ("Guardian" was the Russian version of "Colossus") appears in at least one segment. Though not immediately verifiable, at least one segment uses the "Colossus" speaker/microphone.
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.