Yes, that really did just happen on Mad Men last night.

The series known for its slow simmer of character build-up and storytelling followed up Joan's bedroom negotiations two weeks ago with the death of a major character. Did anyone see that coming?!?

How will Don Draper and company react on next Sunday's season five finale? As usual, AMC hasn't revealed much in its official synopsis ("Season 5 concludes with opportunities abounding for everyone at the agency, while Pete encounters an interesting stranger on a train.") or its official trailer.

But you can still get some idea of what's to come in the following footage:

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.