Ep 22. Nemesis

As the season 3 finale, "Nemesis" sees the SG-1 team returning to Earth following their defeat of the Goa'uld System Lord Seth. Upon their return, the team finds out that the NID has been conducting experiments on a captive alien creature known as "Unas." When the creature escapes from their custody, it begins to wreak havoc on the SGC and the surrounding area.

The SG-1 team, along with General Hammond, devise a plan to capture the creature and return it to its home planet. Along the way, they discover a new enemy in the form of an advanced race of beings known as the "Aschen." These beings offer the Earth an alliance, promising advanced technology and a peaceful alliance in exchange for their protection and an unequal partnership.

However, as the SG-1 team investigates further, they uncover the terrible truth behind the Aschen's offer - they aim to sterilize the human race and use Earth as a new home for their own people. With time running out, the team must work together to expose the Aschen's true intentions and prevent the destruction of humanity.

Throughout "Nemesis," the SG-1 team must contend with not only the threat of the Aschen, but also with personal demons and difficult decisions. For instance, Samantha Carter faces her own mortality as she struggles to save the life of an injured team member, while Daniel Jackson is forced to confront the harsh reality of the Goa'uld's true nature.

As the season finale, "Nemesis" offers plenty of action, drama, and suspense as the SG-1 team faces its greatest challenge yet. With twists and turns aplenty, this episode serves as a thrilling conclusion to an already exciting season, leaving fans eager for more.