Synopsis by Hal Erickson
Season Four of Stargate SG-1 begins where the cliffhanger finale of Season Three left off, with a deadly and apparently unstoppable swarm of replicator bugs threatening to invade the earth. At the last minute, the invasion is thwarted and most of the bugs destroyed. Alas, one of the tiny scourges has managed to infiltrate the Russian submarine Blackbird and is rapidly spawning replicants. Since the Pentagon cannot destroy the sub without seriously damaging US-Soviet relations, the SG-1 team launches not one but two desperate schemes to save the day.