When Dr. Lou Welcome fills in last minute for his boss at a national conference in Atlanta he brings along his best friend, Cap Duncan. But an accident turns tragic when Cap injures his leg while running. ; Surgeons manage to save the leg, but the open wound is the perfect breeding ground for a deadly microbial invader committed to eating Cap alive from the inside out. Meanwhile, hundreds of miles away, a teenaged girl is fighting for her life against the same bacteria. The germ is resistant to any known antibiotic and the government scientist tasked with finding a cure has been kidnapped.