In the season 3 finale of Mad Men, “Shut the Door. Have a Seat.” (AMC, November 8, 2009), Don Draper and three partners plan to leave Sterling Cooper and start a new agency. They have one weekend to get as many accounts as they can.
Don and Roger Sterling visit Pete Campbell at home. Pete has called in sick to interview with a rival agency. They offer him a junior partnership, and he agrees. Pete joins the new firm, Sterling Cooper Draper Pryce, and brings his Sterling Cooper clients with him. The new agency first meets in a hotel room at The Pierre.