The fifth season of the military science fiction television series Stargate SG-1 commenced airing on Showtime in the United States on June 29, 2001, concluded on Sky1 in the United Kingdom on February 6, 2002, and contained 22 episodes. The fifth season introduces future main character from Jonas Quinn portrayed by Corin Nemec from 2002–2004. The fifth season is about the ongoing war with the Goa'uld Empire after the death of Apophis at the start of the season and the rise of a new System Lord named Anubis. SG-1, a military-science team, are set to explore the Milky Way Galaxy.
The one-hour premiere "Enemies", which debuted on June 29, 2001 on Showtime had the lowest syndication of the seasons episode, but overall got a high viewership level. This would be the last season to feature Apophis alive, but he would return in dreams and alternate realities and timelines. The series was developed by Brad Wright and Jonathan Glassner. Season five regular cast members include Richard Dean Anderson, Michael Shanks, Amanda Tapping, Christopher Judge, and Don S. Davis.
SG-1 finds themselves stranded in a crippled ship in a distant galaxy -- with Apophis threatening to destroy them. Teal'c is brainwashed and made loyal to Apophis once again.
His mind altered by Apophis, Teal'c must undergo a ritual that takes him to the edge of death itself, in order for him to rediscover who he is.
An alien being is smitten with Carter and follows her back to Earth. It assumes a human form and pursues a relationship with her.
O'Neill and Lieutenant Tyler are ambushed by Goa'uld forces and trapped behind enemy lines -- while the rest of their team discover they don't know who Tyler is.
SG-1 discovers that their recent trip through the Stargate may have inadvertently doomed an entire civilization.
Cassandra mysteriously falls ill, sending SG-1 back to her home planet -- where they uncover a dark Goa'uld secret.
SG-1 discovers a civilization that uses Unas as slave labor, and attempt to liberate Daniel's friend, Chaka.
SG-1 teams with a Russian unit when one of their Stargate teams goes missing in a mysterious alien ziggurat.
The Tollan offer Earth advanced weapons technology, prompting a secret investigation on Tollana -- one that leads to a startling discovery.
SG-1 encounters a potential new, technologically advanced ally in the war against the Goa'uld -- though they do not know the Aschen's dark secret.
When Carter goes missing, O'Neill teams up with Col. Maybourne again to free her.
An alien ship approaches Earth, sending SG-1 to an old friend for some answers -- where they discover that Martin Lloyd has created a TV show about the Stargate program.
SG-1 trains a team of raw cadets, and Colonel O'Neill is forced to take them into a real-life battle situation when he learns of a possible alien incursion at the SGC.
Disaster strikes the Stargate, trapping Teal'c in transit. SG-1 must turn to Russia -- and to their enemies -- for help.
The Tok'ra war with the Goa'uld escalates, and the rebel faction sends Daniel Jackson to a secret meeting between the System Lords.
Dr. Jackson's undercover mission to a Goa'uld summit is complicated by the arrival of a surprise guest. The rest of the team face a full-scale invasion of the Tok'ra homeworld.
Earth finds itself threatened by something even larger than the Goa'uld when the team learns that an asteroid is on a collision course with the planet.
A charismatic Jaffa leader seeks to forge an alliance between Earth and his rebel followers, winning the allegiance of Teal'c and Bra'tac.
SG-1 encounters a young woman with the ability to control Replicators, and who may hold the key to the salvation of the Asgard.
SG-1 must turn to a pair of convicted criminals to save a world from annihilation by the Goa'uld.
Daniel Jackson is exposed to a lethal dose of radiation while visiting an alien civilization that is building a weapon of mass destruction.