Renegade USAF General Lawrence Dell (Lancaster) escapes from a military prison and takes over an ICBM silo near Montana, threatening to launch its missiles and start World War III unless the President (Durning) reveals a top secret document about The Vietnam War to the American people.
This film contains examples of:
- Artistic License Military: One of the uglier kinds of "license" available: once the Two-Keyed Lock of a nuclear missile is activated, there is no way to cancel the launch. At all. Dell's attempt at playing chicken around halfway in the film would have ended with him triggering World War III in Real Life.
- Downer Ending: The military-industrial complex kills Dell and the President of the United States to keep quiet about their dastardly deeds in Vietnam.
- Empty Quiver: Dell and his crew take over a missile silo with full intent to send the missiles away and risk starting World War III if Dell's demands aren't met.
- The Film of the Book: Adapted from the 1971 novel Viper Three by Walter Wager.
- Godzilla Threshold:
- The whole film is Dell's. He tried to gather the information he needed about the conspiracy through regular means. He was sent to Leavenworth on fake charges as a result. Now he's got nothing left to lose...
- A commando team sent into the missile silo to try to break into the control room and take out Dell is bringing along a miniature shaped-charge nuclear bomb to punch through the control room's reinforced door. It carries the possibility of the team getting blown up, fatally irradiated, or the control room being wrecked and maybe launch the nukes accidentally, but as long as Dell has his hand over the launch button the military doesn't sees any other choice. Dell ends up having to start the launch procedure of one of the missiles in a game of chicken to force the team to back off.
- Government Conspiracy: The reason why The Vietnam War occurred? Not completely because it was the political thing to do. The MacGuffin Dell tries to obtain by (nuclear) crook is the documentation that proves the extent of the calamities made by the government, which they are willing to kill to keep secret.
- The Last Title: Twilight's Last Gleaming
- Literary Allusion Title: The film's title is taken from "The Star-Spangled Banner", the national anthem of the United States:O say, can you see, by the dawn's early light / what so proudly we hailed at the twilight's last gleaming.
- Prove I Am Not Bluffing: One of the most tense moments of the film is Dell spinning up the missiles and getting them ready to launch while on the phone with one of the negotiating agents, ordering the retreat of a commando team that has made it into the base or else he will let one go.
- Psycho Party Member: Defied when it becomes apparent that Hoxey is one of these (killing a couple of guards while they are being Mugged for Disguise because, in his words, "I don't like officers" -bear in mind that he was asked not to do that), General Dell waits until they are within the silo's primary entrance to kill Hoxey. The problem for Dell then becomes that Hoxey was the only guy of the team that knew how to do Safe Cracking, and so they need to improvise a way to get the combination from the silo's personnel/hostages so they can launch the missiles...