“Enemies” is episode one of season five of Stargate SG-1.
In the season four finale, “Exodus”, after blowing up a star to destroy a Goa’uld fleet, the Goa’uld mothership that most of SG-1 was on (excluding Teal’c, who had been captured by Apophis), had been sent 4 million light years through space, well beyond the ship’s capabilities normally, and apparently 125 years at maximum speed from where they were. The ships are an awful lot faster than they used to be, when they were originally stated to need several years to travel a couple of dozen light years or so.
It seemed the supernova had interfered and sent the ship far across space. Even worse, although much of Apophis’s fleet had been destroyed, his command ship (which is much bigger than the other motherships) had been sent to the same destination. And Apophis is none too happy, and is going to destroy them – until another ship intervenes.
This is not good news though, as the other ship is a Replicator ship. Not exactly the best choice for a rescue.