This week, Jim and Pam returned from Costa Rica, full of in-jokes - "Frank and Beans!" - and Puerto Rican candy for their office mates. Shortly upon their return, Michael makes a shocking disclosure to Jim - he's dating Pam's recently divorced mother. Jim advises him to never, ever tell Pam, but after Erin accidentally reveals that Michael is going on a date that night, Pam begs to know who his new girlfriend is. After trying to hedge, he finally reveals the truth.
Pam then proceeds to go off the deep end, running to the parking lot screaming, calling and berating her mother, and generally being kind of a jerk to Michael and everyone else in the office. The real reason that Pam is upset is never really made clear - it mostly hinges on the "Ew!" factor (understandable) and how awkward it makes things for her.
But really, she's the one making it super awkward for everyone, openly criticizing Michael for non-Mom dating crimes. The rest of the office is split, some taking Pam's side that Michael crossed the line by even considering dating a co-worker's parent, while others say that Pam's mom is an adult, able to make her own decisions.
As the episode progressed and Pam refused to get less angry, Michael became more and more sympathetic, even comforting Pam's mother after Pam harshly berates her. At the end of the episode, Pam seems slightly mollified, but still pretty irate.
The sub plot this week is that Dwight gives Jim a wooden mallard with a listening device implanted in it, so he can "surveil" Jim. Jim figures this out, and pulls some pranks on Dwight. Finally, he reveals that he knows the duck (mallard!) is a listening device, and makes Dwight wash and buff Pam's car.
BUT, at the end we see that the real surveillance device is installed in the tip of one of Jim's pens, and the mallard was only a decoy. Oh Dwight, so wily. The episode ends with him listening intently as Jim yammers about different types of paper to a customer. Who knows what damning secrets Dwight may hear?
Moving forward, I don't know how they're going to make it work with Michael and Pam's mom. It is, admittedly, pretty sketchy, but Michael seems truly happy with her, and Pam's mom clearly likes him too. Will Pam get over it? Will they double date? It was nice to see Pam stretch her character a little, rather than the same old "nice, and slightly awkward" thing she's had going thus far. I'm all for a full range of emotion, but let's try to make it a little more relatable next time.