Avalon, Part 1

Avalon is the first episode of the ninth season of Stargate SG-1.

Plot
Colonel Cameron Mitchell is at Stargate Command staring at the Stargate for the first time. He piloted one of the F-302's in the defence of Earth against the attack fleet of Anubis at the climax of season 7. After his heroic efforts and recovery from injury, Jack O'Neill offered him any job he liked, and he wished to join SG-1. However, when he arrives at the base, he finds that SG-1 has been disbanded, a new general is in control, and he is set to pick and lead the new team.

The new general is Gen. Hank Landry, a friend of both George Hammond and Jack O'Neill. Under his order, Mitchell begins the selection process for new members of SG-1, but can't stomach any of the terrible candidates. He wanted to work with the best, and he's determined to get SG-1 back together.

Teal'c is off world on the planet Dakara, which has been established as the capital of the newly founded Free Jaffa Nation, the aftermath of the fall of the Goa'uld at the end of Season 8. Samantha Carter has been moved to Area 51, where she is aiding the research. Jack O'Neill has been promoted out of the SGC (hence the new general), and Daniel Jackson is set to take a ride on board the Daedalus, the newest Earth intergalactic battlecruiser, to Atlantis, the now-found City of the Ancients.

An unscheduled offworld activation admits to the SGC a character not seen since Season 8 - Vala Mal Doran - claiming to have something they want. They let her in and she immediately seeks out her "friend" Daniel to pester. She's got a tablet written in Ancient that leads to a trove of hidden Ancient treasures, and she needs Daniel to translate it. However, as soon as they are close together, she throws a pair of cuffs onto both his and her wrists. These are Kormac Bracelets (Teal'c explains, on his return), which link the two of them together such that they cannot be greatly separated without feeling pain and eventually death. Thus Vala ensures that Daniel does what she says.

This, of course, causes Daniel to miss his trip on the Daedalus to Atlantis, meaning that he won't make his much-desired trip there. Meanwhile however, he translates the tablet and who wrote it: an Ancient fleeing Atlantis after the war with the Wraith, named Myrddin, who Daniel says is Merlin, the wizard associated with King Arthur and his Knights of the Round Table. After further research, Daniel concludes that the treasure is located beneath Glastonbury Tor in England.

Arriving at the place on the Prometheus, they ring inside a hidden cavern where a hologram of Merlin tells them that only the true will gain access to the treasures of the Ancients. There is a sword in a stone, but Mitchell is unable to remove it. They decide to explore further; Daniel and Vala take a right passageway, and Mitchell and Teal'c take a left.

Both parties find rooms which light up upon entry. In both rooms, the parties encounter puzzles, and the doors lock shut automatically. Just when they think it can't get any worse, the ceiling begins to lower to crush them, and they must solve the puzzles in time before they are crushed.