Shouichi encounters a teenage girl called Sayaka, who ran away from a military facility because of an attack by the Ant Lords. Sayaka has a supernatural ability to foresee the future. Risa Fukami, of the military group GA, wants to use that power to enhance the newly-made G4 System, which was based upon designs stolen from Ozawa.
Now, Agito and Gills must fight to stop the Ant Lords' attack, as G3 and G4 settle their score.
This is the first Movie to feature a Movie Exclusive Rider, as from then on, many Kamen Rider movies would adapt this concept.
This film opens with a credit stating the movie was made to commemorate the 50th anniversary of Toei Company (which was founded in 1950).
Another credit follows immediately afterward stating the film is also a Kamen Rider 30th Anniversary work.
The film features a product placement plug for the American fast food restaurant chain Wendy's. A few scenes in the film features the restaurant prominently and has Shouichi, Mana and Sayaka eating there. The camera even starts the scene on a close up shot of a customer eating the food so viewers could see the label.
When Ryo transforms into Kamen Rider Gills for the first time in the movie, the image of Gills does not line up with where he is standing.
One of the Ant Lords that Agito Flame form fights is a damaged costume that has a gash on the seat of the pants section of the suit. This is visible as its back is facing towards the camera.
Before G4 uses the Gigant, he connects the power cable to his belt to activate the launcher. When the Gigant fires the missiles, G4's power cable is somehow no longer connected to the belt.