In the New Mexico desert, police sergeant Ben Peterson and trooper Ed Blackburn find a girl wandering by herself and clearly in shock. A little further on they discover a completely destroyed trailer. A nearby store also turns out to be destroyed. The FBI is called in and they find strange footprints – of ants. Asked to assist, myrmecologists (ant scientists) Dr. Harold Medford and his daughter, Dr. Pat Medford, make a terrible discovery: the atomic tests of ten years ago have led to the mutation of ants into giant, murderous creatures. The army manages to destroy the ants' nest, but two queen ants escape.
The film was originally conceived to be in colour and in 3D, however the 3D camera malfunctioned during the filming of the first test shots. So the studio bosses decided to scrap 3D and colour. Only the opening credits are in colour. The plan to film in widescreen never materialized either. Still, the film was nominated for an Oscar for its special effects.