Alias follows the life of Sydney Bristow, an intelligence agent who supposedly works for a black ops division of the CIA, SD-6. When she tells her fiance about her job (her cover is that she works for a local bank, Credit Dauphine), SD-6 finds out and has him killed, and they now think she is a double agent, so they try to kill her, too. Her estranged father saves her and tells her that she really works for the bad guys, like he does. She's believed for many years that he sold airplane parts, but instead he works for SD-6. He's one of the few people who knows the truth about them. Every agent believes that SD-6 is part a the CIA, which it isn't. It is part of the Alliance of Twelve, a group of rogue agents that are an enemy of the USA. Sydney retrieves something of value for SD-6, earning their trust again, and then proceeds to the real CIA for help taking down SD-6. She's now a double agent for the real CIA in SD-6.