Don is greeted with a surprise in the Season 5 opener. Meanwhile, Roger and Pete clash; and Joan has a run-in with a houseguest.

Don is greeted with a surprise in the Season 5 opener. Meanwhile, Roger and Pete clash; and Joan has a run-in with a houseguest.

Peggy receives new responsibilities as the firm makes a concentrated push to increase business. Later, Don and Harry go the extra mile for a big client.

Don has an encounter with someone from the past; Joan comes to a momentous decision. Meanwhile, Roger increases Peggy's workload.

Lane makes an interesting friend; Pete plays host to an assortment of guests.

Peggy has a tough time during a particularly formidable pitch; Don calls on a potential client.

Don, Roger and Pete team up to rustle up some new clients; Sally lends a hand to a relative.

Peggy becomes angry when she is forced to keep a secret she doesn't want to keep; Pete sticks his neck out for a friend; Don receives surprising news.

Don's competitive nature comes to the fore; Roger pursues some new clients; Sally is met with a challenge.

Christmas proves rewarding to many at the agency; Harry does a good turn for a friend.

Pete asks Joan to make a personal and moral sacrifice to ensure the company lands the Jaguar account. Don becomes furious after learning of the impact Megan's new profession will have on their life. Feeling unappreciated, Peggy attends lunch with Freddy Rumsen, who encourages her to make a move.

Lane's shameful secret comes to the surface with dire consequences. Don recaptures his hunger for success, and Sally experiences a major milestone.

Roger seeks to expand his affair with Megan's mother. Pete has a "last" encounter with Beth with lasting repercussions. Megan struggles to find acting work and asks for Don's help getting an audition. Peggy still seeks Don's approval.