The series picked up seven or eight months after the fourth season finale. Don and Megan are married and can't keep their hands off of each other. They still have their issues, which arise when Megan throws Don a surprise 40th birthday party.
Pete and Roger are fighting over clients, but Pete continues to bring in almost all of the money at SCDP. Joan had her baby and is having a difficult time dealing with that and not working. Lane finds a lost wallet and tries to have a rendezvous with the owner's girlfriend.