An ex-major forces a scientist to develop a invisibility formula, with which he plans to create an invisible army and sell it to the highest bidder. However there are side effects to the formula.

Scientist Dr. Bradford Crane and army general Thalius Slater join forces to fight an almost invisible enemy threatening America; killer bees that have deadly venom and attack without reason. Disaster movie-master Irwin Allen’s film contains spectacular special effects, including a train crash caused by the eponymous swarm.