Sydney's search for her past leads to a jailed Sark, but their Q&A is cut short when he becomes the ransom for a pair of abducted CIA scientists, whose kidnappers may be tied to the murder of his father. Jack contacts an old friend of sorts for info on Sloane's new world-peace project, and Vaughn makes a decision about his future as an operative.

Sydney finally learns the shocking truth about her missing two years from an unlikely source.