It was New Year's Eve 1964. Don goes to California and learns that the original Mrs. Draper, Anna, has cancer. After finding out her sister and niece haven't told her about, he eventually decides to do the same.  He also hits on the niece, gets shut down, and leaves Cali.

Don comes back to an empty office.  That is empty except Lane, who is still frustrated over both the financial problems of the agency and his personal loneliness over the holiday.

Don and Lane hit the town with a movie, a restaurant a comedy show and finish it off with a couple of prostitutes.

Joan deals with the continued stress of her job and her husband.  She can't take a vacation from work because her doctor of a husband can't get New Year's off.  But because of the problems at the office, she's not allowed to get off of work later in the month.