When a small Illinois town vanishes off the map in a single night, Intrepid Reporter Audrey Aimes (Peggie Castle) swoops in smelling a scoop. Denied this, she begins investigating the goings on, leading her to Dr. Ed Wainwright (Peter Graves), who has developed a greenhouse full of atomic-sized fruits and vegetablesnote — which the local insect population keeps breaking into.
Continuing the investigation, Audrey and Peter eventually discover the culprit: LOCUSTS! BIG ONES!! Irradiated by the good doctor's atomic plants, the local locust population has been transformed into a Nigh-Invulnerable swarm of eight-foot-plus bugs of DOOM! The giant bugs begin chowing down on (postcards of) the Illinois countryside and work their way toward Chicago while Dr. Wainwright tries to figure out how to stop them.
Beginning Of The End provides examples of:
- Artistic License Geography:
- The locust swarm goes from Rantoul to Chicago... by way of Peoria (making a substantial detour to the west, for those who don't have a map of Illinois handy).
- Also, the infamous "suburbs of Paxton." Paxton, Illinois, is a small rural town (population slightly under 4,500 as of 2010) which has never had suburbs. They might have meant it was "the suburb (of) Paxton", but even this would be wrong because Paxton is a standalone town.
- Attack of the 50-Foot Whatever: Actually, the script mentions that the Big Bugs come in various sizes, in an effort to cover the lousy compositing work.
- Auto Erotica: The couple in the Cold Open only manage to get to first base before they're killed off though.
- Big Creepy-Crawlies: The locusts, of course.
- Chickification: Audrey Aimes goes from Intrepid Reporter in the first half of the movie to Neutral Female in the latter half.
- Giant Food: Subverted; Wainwright's bowling-ball-sized strawberries and other oversized produce aren't safe for human consumption.
- Godzilla Threshold: The Army is willing to nuke Chicago to stop the locusts.
- Just Plane Wrong: The film bungles its one specific equipment call - the general says a B-52 will be used to nuke the grasshoppers. The stock footage used to portray the bomber is of a B-36, though. Either plane would be correct if the movie was consistent; it was produced and released in the brief window when the Air Force was transitioning between the two.
- More Dakka: When Wainwright gets his hands on a military submachinegun.
- The Mountains of Illinois: The Trope Namer!
- The area around Paxton and especially Ludlow is shown to be very hilly and mountain-y. In reality, the landscape in the Champaign/Urbana/Ludlow/Paxton region is quite flat.
- Additionally, establishing shots of Audrey driving down an Illinois highway show a very visible mountain range in the background. There is nowhere in the entire state where you could view such a mountain range.
- Omnidisciplinary Scientist: Played with:
- Ed Wainwright is the lead scientist on the atomic agriculture project, but he's an entomologist (study of insects), whereas his assistant Frank is the actual botanist. Ed notes that he and Frank are teaching each other about their respective specialties.
- Taken further with Ed, who notes that he was interested in electronics at a young age and served as a radio/electronics operator during "the war", which knowledge ends up playing into the climax.
- Police Are Useless: Audrey invokes this to justify her continued investigation into things: "The sheriff thinks in terms of 'crime and publicity'. You're a scientist; you think in terms of 'cause and effect'; maybe you'll see something the sheriff missed."
- Real Life Writes the Plot: A rather creepy example, as we see fewer and fewer locusts onscreen at once as the film goes on, as they had started eating each other.
- Retirony: Major Everett: "You know, I'm 37 years old, and I've just realized how much I've taken life for granted." Not five minutes later, the man is dead.
- Romantic False Lead: Captain Barton is set up as this early on. Problem is, he vanishes halfway through the movie, along with the rest of Paxton.
- The Speechless: Deaf/mute Frank.
- Suspiciously Similar Substitute: A same-work example, as Major Everett steps into the role left vacant by the recently departed Captain Barton.
- Title Drop: "Annihilation... the beginning of the end."
- You Have to Believe Me!: Played hilariously straight even as Dr. Wainwright intones, "You know I'm not given to hysteria and you've got to listen to me with an open mind!"