Kingdom of the Spiders was directed by John “Bud” Cardos and produced by Igo Kantor, Jeffrey M. Sneller and James Bond Johnson. The screenplay is credited to Richard Robinson and Alan Caillou, from an original story by Jeffrey M. Sneller and Stephen Lodge. The film was released by Dimension Pictures (not to be confused with the distributor Dimension Films). It stars William Shatner, Tiffany Bolling, Woody Strode, Lieux Dressler, and Altovise Davis.
Shatner plays Robert “Rack” Hansen, a veterinarian in rural Verde Valley, Arizona, United State. Rack receives an urgent call from an upset local farmer called Walter Colby who is distraught because his prize calf has become sick for no apparent reason, a. Colby brings the animal to Rack’s laboratory where it is examined and dies shortly afterward. Rack tells Colby he cannot explain what made the animal so ill so quickly, but takes samples of the calf’s blood to a university lab in Flagstaff.
A few days later, Diane Ashley (Bolling), an arachnologist, arrives looking for Rack. Ashley tells Rack that the calf was killed by a massive dose of spider venom, which Rack greets with skepticism. Undaunted, Ashley tells him the problem is serious and that she wishes to examine the animal’s carcass and the area where it became sick.
Rack escorts Ashley to Colby’s farm. Moments after they arrive, Colby’s wife, Birch (Altovise Davis), discovers their dog is dead. Ashley performs a quick chemical test on the dog’s carcass and concludes that like the calf, it died from a massive injection of spider venom. Rack is incredulous, until Colby states that he recently found a massive “spider hill” on a back section of his farmland. He takes Rack and Ashley to the hill, which is covered with tarantulas. Ashley theorizes that the tarantulas are converging together due to the heavy use of pesticides, which are eradicating their natural food supply. In order to survive, the spiders are joining forces to attack and eat larger animals…