An alien force live among human species. Growing in number and breeding with humans, the aliens' mission is to annihilate human organisms. Their plan is called Hell Swarm, and it has already begun... Accused of murdering his partner, policeman Billy Sabbath has just been executed by the authorities, but Billy's execution was a ruse, staged by top government agent who needs Billy for a secret command unit to fight the aliens. Known as the Phylum, the aliens appear to be human, but are endowed with far superior strength and a plan - the first day of spring, they will release millions of bees infected with a toxic venom, and unless Billy can destroy their operation first, mankind will discover hell on earth.