S4, E15: When Lt. Colonel John Sheppard (Joe Flanigan) is informed that his father has passed away he packs a few things and accompanied by Ronan (Jason Momoa) heads back to Earth to attend the funeral.  There Ronan gains some insights to his friend's past - Sheppard's troubled relationship with his father and brother as well as his ex-wife Nancy a director with Homeland Security.  Before long they are approached by a woman Ava Dixon who claims to know about a covert project involving nanite programming. Sheppard's worst fears are realized when she leads them to a high tech lab and reveals that she and her partner have been successful in creating a human form Replicator - a Replicator now loose somewhere in the city who must be recaptured at all cost.