Basically no plot. Only character development was Peggy increasingly waking up to the fact that she is the one who should actually be in charge.
Pretty great on establishing the atmosphere of fear and loathing/darkness that Hunter Thompson and Norman Mailer tells us was characteristic of the time. Crime, parental neglect, Vietnam, teen sex, bad drug trips, corporate malfunctioning and the general sense that the inmates had taken over the asylum. Genuinely disturbing.
Don & Sylvia on the elevator was great. She didn't realize that the elevator freeze-out is Draper's favorite trick.