“Serpent’s Song” is episode eighteen of season two of Stargate SG-1.
SG-1 are following up a tip from the Tok’ra when a death glider crashes nearby. Inside it is an injured Goa’uld who asks for help – Apophis.
More death gliders attack, seeking to capture Apophis, who wants sanctuary from the SGC. Not an idea that’s universally popular. Hardly surprising that, really. It seems that Apophis has suffered a major setback after the SGC destroyed his ships in “The Serpent’s Lair” and an old, powerful Goa’uld has returned, Sokar.
Apophis offers all his knowledge in exchange for a new host.
(PickTV got some of the episodes in the wrong order when I watched this; two of the previous episodes were in the wrong order, and episode seventeen, “Holiday”, the one before this one hadn’t been shown yet. Fortunately, in this case, this wasn’t a huge problem, but sometimes this could be.)