Due to some unknown cosmic event, listed in “phases,” ants have undergone rapid evolution and developed a hive mind. A scientific team begins investigating strange towers and geometrically perfect designs that the ants have started building in the desert. The ant colony and the scientific team, along with a rural family, make war with each other, with the ants being the more effective aggressors. The narrative uses the scientific team as the main protagonists, but also an ant “heroine” going about her duties in the colony. The film concludes with the last of the cosmic “phases,” Phase IV, which promises a new future for all life on Earth.
Despite the lurid tone of its poster art based on one of the shocking images from the film, Phase IV approaches its subject matter naturalistically, with relatively little melodrama. The film contains relatively little dialogue, mainly relaying the storyline visually.
According to the IMDb, Bass complained in interviews that the film was re-edited after previews by 20th Century Fox radically altering the ending of the film which consisted of surreal images presented in a montage. The montage was supposed to suggest that the two surviving characters were altered by the ants creating the next step in evolution for humanity and insects. Many of the images from the altered conclusion of the film appear in the trailer and although it has recently been released to home video by Legend Films, the reissue on DVD features the shorter U.S. version which had 9 minutes stripped from the film before its official U.S. debut.
The film was a box office flop and as a result this was the only feature film directed by Bass.
Thanks to Maxime for the suggestion!