Chris is so excited to hear that Leslie and Ben are engaged that he wants to accompany them around while they tell their other coworkers the news. However, Chris doesn't know that he is actually the last one in the office to find out, but Ben and Leslie go around telling everyone again that they're engaged, and are met with half-hearted reactions.
Leslie and Ben comb out the final details of their engagement party with Ann. Everything seems to be in place, but Ben is intent on canceling the party altogether since both of his parents are coming. His parents were divorced 30 years ago, and they still hate each other with a burning passion. So much so, they can't even be in the same room together. Leslie is determined to change this and assures Ben that the Knope-Wyatt Unity Quilt she made will fix everything.
Meanwhile, Tom and Jean-Ralphio work on a pitch for Tom's next big business venture: Rent-A-Swag. Ron has agreed to listen to Tom's pitch and consider investing some start-up money. Tom and Jean-Ralphio rehearse their flashy presentation for April, who bluntly tells Tom that Ron is going to hate it. If he's really serious about impressing Ron, she tells him he should drop the act and focus on the facts.
Chris has an emotional breakdown at Leslie and Ben's engagement party, completely raw from therapy. He's so happy for his friends, but at the same time so depressed at the realization that he's completely and totally alone. Ann has no choice but to comfort Chris, and recruits April and Andy to try to help bring him out of his depression. They try some unusual tactics, but eventually manage to drag him back to reality.
When Ben's parents finally arrive, all hell breaks loose. Ben's father, Steve Wyatt, brings his much younger girlfriend, Ulani, whom Ben's mother completely detests. The two waste no time taking shots at each other, and their catty behavior becomes completely unbearable. Leslie does her best to diffuse the situation, but Ulani's presence was something Leslie and Ben hadn't predicted.
In a last ditch effort, Leslie unveils the Knope-Wyatt Unity Quilt in all its glory. For a moment, the two families are awestruck by Leslie's amazing creation; it's truly a beautiful quilt. Each family member is represented with his or her own square on the quilt, which Leslie thoughtfully created by hand. But Ben's father ruins the moment - why doesn't Ulani have a square? Leslie claims that she can create a square for her and haphazardly writes Ulani on one of the squares in permanent marker. This only serves to enrage Julia Wyatt, and the two are at each other's throats again. Then, Ulani drops a bomb: Ulani really is about to be a part of the family because she's pregnant with Ben's father's baby.
Tom's got his work cut out for him and is ready to pull an all-nighter redoing his pitch for Ron. And when he realizes that Jean-Ralphio is more concerned with clubbing than spending time preparing the pitch, he decides that maybe he should make a go at this business venture on his own. The next morning, before his pitch, Tom lets Ron know that Jean-Ralphio is no longer a part of the company because he wasn't ready to take it seriously. Ron agrees to fund Tom on the spot, stating that dropping Jean-Ralphio for the good of the business was the only convincing he needs.
The dust eventually settles from the fight (but not until Ben's mom takes scissors to the quilt, removing Ulani's square altogether). Ben and Leslie sit down their family members to give them a talking to. They explain that they don't expect Ben's parents to like each other - in fact they'd prefer it if they didn't socialize - but they both have to come to the wedding. And they have to put on a smile and pretend that they're having a great time. Both apologize for their childish behavior and agree to Leslie and Ben's terms. Leslie later points out that even though Ben's parents are insane, he's amazing. And that's all that matters.