Ep 20. Camelot

While the Stargate program is on the brink of being shut down, SG-1 receives news of the mysterious Atlantis outpost, believed to be in Antarctica. O'Neill and Carter head a reconnaissance mission to the outpost, seemingly deserted by the Ancients, that yields a wealth of new technology and information. But the return trip through the wormhole turns into a disaster as the team emerges in a world littered with blood-red vegetation and lethal creatures.

SG-1 struggles to elude their new pursuers, the Ori soldiers, armed with staff weapons which easily blast through the thick forest and plow the landscape. Trapped and getting cut off from each other, the team eventually reunites on one edge of a caldera - and witnesses the missile launch from one of the Ori warships. A giant energy blast engulfs the area, knocking them all unconscious.

When they wake up, they find themselves in a medieval castle, tended by a beautiful woman, called Lady of the Lake, who claims to be the sole survivor of a terrible plague that ravaged the planet. Carter discovers that the woman has a stasis chamber full of soldiers, all with the emblem of King Arthur ap Camelot on their shields. Slowly, the story behind the woman and her castle begins to emerge – she’s part of a long line of women who guard the chamber until Arthur returns to save the world.

Despite the danger that the Ori pose to their mission, SG-1 agrees to help the woman, and some of the knights awaken from stasis. They stand with Daniel, Mitchell and Teal'c against the Ori invasion, building weapons and learning to fight in the old ways. SG-1 also learns that Merlin, who helped King Arthur once before, left instructions for a powerful weapon hidden in the castle and that whoever wields it can save them all.

Carter manages to decipher the encryption and retrieves the weapon: a Personal Intergalactic Communication or PIC - a tiny, replicable version of the Stargate. However, the assembly instructions for the device remain incomplete. Daniel pieces together the missing parts, believing he’s following the true path that Merlin envisioned. As SG-1 and the knights make their final stand against the Ori, Daniel assembles the PIC, sacrifices himself to activate it, and sends the calling card to the only person who may be able to help them...

The end of the episode turns a corner for the team, and sets them on a new path for upcoming seasons, as they face a galaxy-changing event, and a new and formidable villain.