S2, E8: There's more than one Observer! When one of the series' mysterious Observers kidnaps a woman, the Fringe team is called in to investigate why. But while the course of their investigation not only reveals the private lives of the Observers, it also threatens to unearth Walter's clandestine involvement with them years before – a secret he's desperate to keep from his son, Peter. As destiny is irrevocably rewritten and time is running out, the renegade Observer asks for help from the unlikeliest of sources…Walter Bishop.