During this season, the head of SD-6, Arvin Sloane, was obsessed with Milo Rambaldi, a man from the 15th century who was able to create brilliant devices that were far ahead of their time. Sydney worked on a number of missions to retrieve or modify these Rambaldi devices to prevent them from falling into the hands of SD-6. During the season finale, on one such mission to destroy such a device, Sydney is captured and discovers that the organization that SD-6 has been pursuing is being run by Irina Derevko, Sydney's mother and a former KGB spy.