It was Family Day at Greendale, which resulted in the following developments:
We met Troy's mean grandmother, who Britta tried to bond with. She did this by actually bringing the woman a "switch" when it was asked for and letting her spank Britta with it. Weird stuff. Guess Troy was right that his grandma was simply not a nice woman.
Meanwhile, Professor Chang's brother is a rabbi. That was funny.
We also got to know Shirley's kids and Abed's father a bit better. The former aren't well-disciplined, and Shirley takes that personally because she doesn't see them often. But they have good hearts, as evidenced by the following: Abed's dad is very strict, especially when it comes to Abed's cousin.
She just wants to have some fun and break free from her berka, but he's having none of that. So, when Mr. Abed leaves briefly, Shirley's kids let the cousin go play, as they both hide under the berka and pretend they are her for her uncle. It sounds confusing, but it was very nice.
The main storyline involved Katharine McPhee as Pierce's step-daughter. Jeff liked her. Jeff had sex with her, even after she told him that she just pockets the large checks Pierce gives her, instead of using them for grad school.
But Jeff's guilt finally gets the best and he tells the step-daughter he's done with her. Pierce is his friend. McPhee's character leaves, still planning on grifting from her step-father, but at least Jeff and Pierce share a nice moment. The former lets the latter in on how much his step-daughter sucks, but also on the fact that Pierce still has a family: his friends.