Season 4

401 _____
06.30.01 Small Victories
 O'Neill, Carter and Teal'c return to Earth. Soon after, O'Neill and Teal'c must risk their lives to keep the Replicator bugs from gaining a foothold on Earth. Meanwhile, Major Carter goes to an Asgard planet to help Thor find a way to defeat the Replicators which are attacking an Asgard planet. (Part 2 of 2)
402 _____
07.07.00 The Other Side
 The SGC receives a distress signal from another planet, which seems to have ties to Earth. The people on the planet are facing extinction at the hands of their enemy, and need our help. SG-1 gates to the planet to offer aid, but as the situation grows more dire, they discover not all is as it seems.
403 _____
07.14.00 Upgrades
 A Tok'ra scientist brings a phenomenal new technology to the SGC: armbands that give the wearer greatly increased strength and speed. They were built by a race called the Atonieks, a now extinct species that predates even the Goa'uld. Guest starring Vanessa Angel as Anise/Freya.
404 _____
07.21.00 Crossroads
 The SGC plays host to a woman from Teal'c's past, a Jaffa who claims she has succeeded in communicating with her symbiote and convincing it to turn against the Goa'uld. If true, the symbiote could offer up a wealth of information. Guest starring Vanessa Angel as Anise/Freya.
405 _____
07.28.00 Divide and Conquer
 When a member of the SGC goes crazy and attempts to kill a Tok'ra official, it is revealed that he was the victim of a Goa'uld mind control process that programs individuals for violent, suicidal acts. The Tok'ra test the rest of the SGC personnel for other victims. Guest starring Vanessa Angel as Anise/Freya.
406 _____
08.04.00 Window of Opportunity
 The SGC is trapped in a temporal anomaly, but only Jack and Teal'c seem to be aware of the fact. They are faced with the dual task of convincing everyone that they're reliving the same six hours over and over again, and trying to find a way to break the time loop.
407 _____
08.11.00 Watergate
 A chance discovery on the ocean floor gives the Russians access to Stargate technology. But when the a Russian scientist turn to the SGC for help, the SG-1 team is led to a remote military installation in Russia - and an unnerving mystery. Guest starring Marina Sirtis as Dr. Svetlana Markov.
408 _____
08.18.00 The First Ones
 While on an archeological expidition on an alien world, Daniel Jackson is captured and held prisoner by an Unas (seen in season two's Demons), and must use his many skills in order to survive. The rest of the SG-1 team go in search of him, but soon run into trouble themselves.
409 _____
08.25.00 Scorched Earth
 SG-1 is caught in a conflict between two civilizations trying to colonize the same planet. The current inhabitants face destruction by the new visitors. SG-1 studies the situation, and concludes that the visitors' vessel is terraforming the planet for a type of life unlike any they know - sulfur-based life, rather than carbon-based.
410 _____
09.01.00 Beneath the Surface
 After visiting a world experiencing an ice age, the minds of Colonel O'Neill and the rest of the SG-1 team are erased by the ruling elite of the planet. They are then used as forced labor in an underground alien facility, under new identities that have been created by their captors.
411 _____
09.08.00 Point of No Return
 SG-1 becomes aware of a conspiracy theorist who has heard rumors about the Stargate. Not only that, but he thinks he's an alien and claims to have vague memories of an alien life. The SG-1 team goes to Montana to investigate this seemingly ludicrous threat.
412 _____
09.15.00 Tangent
 Using two recovered Goa'uld death gliders, Area 51 personnel have created a hybrid vessel that looks like a Goa'uld death glider on the outside, and a jet plane on the inside. Colonel O'Neill and Teal'c take the new craft out for a simple test, but they are soon marooned in space.
413 _____
09.22.00 The Curse
 Daniel discovers that his mentor, Dr. Jordan, was killed in a lab explosion while analyzing the Osiris Jar, an artifact recently recovered from a "cursed" 1931 expedition to Egypt. Jackson travels to Chicago to attend the funeral and see his friends and former collegues again.
414 _____
09.29.00 The Serpent's Venom
 When Apophis and Heru'ur decide to enter into an alliance, SG-1 must try to stop them. Teal'c goes to Chulak in an effort to recruit some of his fellow Jaffa warriors to help fight the Goa'uld. On Earth, Jacob Carter and the SGC receive a transmission from the Tok'ra through the Stargate.
415 _____
01.05.01 Chain Reaction
 The SG-1 team must adjust to a new commanding officer, because General Hammond decides to step down as commander of the SGC. Shortly after, O'Neill discovers foul play behind the general's resignation, and he must team up with a former enemy to get to the bottom it.
416 _____
01.12.01 2010
 Ten years into the future, Samantha Carter and Doctor Fraiser have discovered a dark secret that threatens the entire human race. The former members of SG-1 must again team up in order to send a message into the past, hopefully to prevent this terrible disaster.
417 _____
01.19.01 Absolute Power
 In an almost magical whirlwind, Daniel is reunited with the Harsesis child, Shifu (last seen in season three's Maternal Instinct). The child teaches Daniel a lesson by giving him some Goa'uld genetic memories and launching him on a spiritual journey. Daniel soon begins to behave erratically.
418 _____
01.26.01 The Light
 Lieutenant Barber of SG-5 unexpectedly commits suicide by jumping into a wormhole vortex. While investigating the cause of Lt. Barber's suicide, the SG-1 team travels to a planet where they find a Goa'uld pleasure palace, and they become transfixed by a beautiful, deadly device inside.
419 _____
02.02.01 Prodigy
 Carter tries to motivate a brilliant, but rebellious student by taking her through the Stargate. But a routine excursion takes a deadly turn when they are attacked by beings of pure energy. The colonel orders everyone back to the Stargate for an immediate evacuation, but a swarm of the life forms block their path.
420 _____
02.09.01 Entity
 The SGC makes contact with a world whose address was taken from the Ancients' repository of knowledge, and sends through a MALP probe. An alien virus infiltrates the SGC computer and gathers classified data. When the virus is presumed killed, it is learned that it has actually sought refuge in Carter's body.
421 _____
02.16.01 Double Jeopardy
The SG-1 team encounters the Goa'uld System Lord Cronus (last seen in season four's Crossroads) while trying to undo a mistake they supposedly made on a prior mission. They confront Cronus with help from an unexpected source.
422 _____
03.10.00 Exodus
 As SG-1 helps to evacuate the Tok'ra from the planet Vorash to a new base, matters are complicated when a spy reveals their location to Apophis. The team attempts a daring plan to take out the Goa'uld's powerful fleet, but the captured spy soon escapes, jeopardizing their plan. (Part 1 of 2)