Ep 1. Avalon: Part 1

SG-1 returns from a mission with several people whom they took aboard a crashed ship, including an injured Lt. Col. Cameron Mitchell. SG Command informs General O'Neill that Dr. Daniel Jackson has been kidnapped by a group of warriors known as the Ori. Daniel had been studying their sacred texts and determined that they worship a powerful being called the Ori, who demand absolute loyalty and will destroy those who defy them. SG Command has also learned that the Ori have dispatched a fleet of ships to destroy Earth. Colonel Mitchell is temporarily assigned to SG-1 in order to complete the team and find out what the Ori are after. SG-1 discovers that there is an ancient weapon called the Sangraal that could defeat the Ori, but to find it they must seek the help of a retired warrior, Merlin, who may have hidden the weapon. Daniel is being held captive on a distant planet, where he meets a woman named Vala Mal Doran, who also seeks the Sangraal. Together, they escape their captors and make their way back to Earth, where they meet up with SG-1. The team is determined to find the Sangraal before the Ori destroy Earth.