Colonel Jack O'Neill lives in retirement, one year after his interplanetary expedition to Abydos. But when a hostile force of aliens resembling the late Ra and his Chulakins invades Earth through the Stargate and kidnaps a female officer, O'Neill is called back to duty to lead a platoon back through the Stargate and eliminate this new threat. Back in Abydos, O'Neill is reunited with Egyptologist Daniel Jackson to help the team determine from which world through the Stargate this new danger originated from.