Serpent's Song

Serpent's Song is the seventeenth episode of the second season of Stargate SG-1.

Plot
Stargate Command receives a set of coordinates which they believe originated from the Tok'ra. They soon send SG-1 to the world when suddenly, a Goa'uld Death glider screeches overhead and crashes nearby. They investigate the crash site and find their long time adversary, Apophis, extremely wounded and begging for help. Knowing he will soon die, the former System Lord asks SG-1 "for sanctuary," and the team reluctantly brings him to Earth. After Apophis must be rushed into operation if he is to live, Sam concludes that he was tortured with the same hand device that was used to kill Jolinar.

With such a valuable source of information, Stargate Command calls the Tok'ra (who send Martouf) and then waste no time interrogating Apophis. In desperation, he asks for a new host, but Jack quickly tells him to "go to hell". Apophis then reveals that he was defeated by a powerful Goa'uld named Sokar, who is an old and extremely powerful Goa'uld and who once lived on Earth where he posed as Satan. Because of this Martouf and Lantash try to persuade SG1 and Hammond to send Apophis back to Sokar but General Hammond refuses.

Soon after, the Stargate activates with Sokar on the other end, who demands his prisoner be returned to him. However, just as the SGC dismisses his demand, Sokar fires a particle accelerator through the gate, heating the Iris to dangerous levels. The SGC resorts to spraying the iris with liquid nitrogen, but its effect is minimal. Daniel suggests dialling out between attacks, exploiting the 38-minute window, the time a Stargate can stay open without additional energy (used in the episode "There But For the Grace of God" for the same purpose). Unfortunately, Sokar easily reopens the gate faster than the SGC (Because a DHD dials faster than the SGC's dialing computer) and resumes his attack.

Over the time every member of SG-1 talks with Apophis. Daniel asks him for his wife Sha're and also reveals to him that it was Daniel, not Heru'ur, who stole the child of Apophis and Amonet. Teal'c happily watches his former master experience pain (he even stops Dr. Fraiser when she wants to help him) and tells him that one day all Jaffa will be free. To end Sokar's attack, it is decided to allow Apophis to die and return him to the planet where he was found. Rapidly aging and weakening, Apophis can no longer control the host body, and Apophis' host emerges and Daniel speaks with him before his death. Daniel gives him an Egyptian funeral that the host would've normally received.

Sam creates a new rapid dialling program that establishes a wormhole before Sokar can attack a third time. The corpse is passed through the gate, and Sokar is apparently satisfied. Martouf reveals that Sokar will surely revive Apophis with a Sarcophagus to torture him as long as he wants. With the threat from Sokar gone, the Tok'ra give General Hammond a Tollan device to contact them with. In return, Jack gives them a GDO for future contact.