Following a mysterious eclipse-like solar event, scientists begin to notice strange and unexplainable behavioral changes in ants. While initially written off as an unconcerning anomaly, it soon becomes apparent that the creatures have developed advanced intelligence along with the ability to work collectively. Scientists Ernest Hubbs and James Lesko have been transferred to a futuristic lab in a remote part of the Arizona desert in which to study these phenomena. However, when the ants begin to attack and kill both wildlife and humans, Hubbs and Lesko realize that the entire human race might now be at a deadly evolutionary disadvantage to the tiny insects…

The sole feature film directed by acclaimed graphic artist Saul Bass, PHASE IV is a landmark of 1970s science fiction as it blends arresting visuals, photographed by Dick Bush (Sorcerer) along with nature photographer Ken Middleham, with a tense and harrowing animal attack narrative.