"You Don't Know What You've Got Till It's Gone" is the fourth episode of Private Practice season six, which originally aired on October 23, 2012, and centers on a missing child in the ER during a power outage. The episode highlights Sheldon's search for the child, conflicts between Addison and Jake, and the introduction of Dr. James Peterson. Read the full episode summary on the Grey's Anatomy Wiki . You Don't Know What You've Got Till It's Gone - Apple TV