As the Replicators overwhelm the new Asgard homeworld, SG-1 works to revive Jack, create an Ancients weapon to stop the invaders, and tries to find the missing Sam, who is held captive by the humanform Replicator Fifth in a virtual reality.

Five days in the life of SGC as Jack assumes full command of the base and has to deal with a rapidly growing alien plant, the capture of SG-1 by Ba'al, arguing alien delegates, and a tricky traitorous System Lord.