While exploring BP6-3Q1, O'Neill and the SG-1 team are attacked by giant insects. The team escapes through the Stargate but not before Teal'c is stung. When Teal'c returns to Earth, a strange transformation begins, as the insect virus transforms Teal'c's DNA into something like its own. The change baffles Dr. Samantha Carter and geneticist Dr. Richard Harlow and it terrifies Teal'c, who makes O'Neill promise he'll stop the transformation. But Tea'lc's condition intrigues Colonel Maybourne who sees the potential for biological weapons in the insect venom. Maybourne uses his presidential mandate to take custody of TEal'c but the Jaffa escapes while being translated, leaving behind his Goa'uld larvae. As Teal'c hides out on the mean streets of the city, he is befriended by Ally, a young homeless girl, Oneill and the team return to BP6-3Q1 to capture the insect. While there, they discover the terrible power of the insects: how they bypass normal breeding by genetically transforming their victims into their offspring. With time being of the essence, the Stargate Command must devise a vaccine and keep the larval Goa'uld alive. Most important of all - they must find Teal'c before Maybourne does.