The Solution is the 20th episode of Season 1 of Alias. In order to catch Khasinau and get closer to finding her mother, Sydney and Vaughn set up an undercover transaction for a Rambaldi artifact with Khasinau's representative, Mr. Sark. But Sydney's cover may be compromised when a SD-6 agent is sent in to thwart the sale. Meanwhile, Will is enticed to continue his investigation of SD-6 when he learns the identity of one of his kidnappers. Emily tells Sydney that she knows about SD-6, which forces Sloane to make the most difficult decision of his life.