Andy takes Nick and Joel to the new Fruitberry Frozen yogurt-shop to pick up on the newest fad. He's forgotten to mention that there's a hot cavewoman, Heather, working at the counter. They all figure Heather is trying to flirt with them. Later Alex brings Kate in but Heather hates her and accuses Joel of dating "smoothies." Joel hems and haws and Kate is furious, wondering why he didn't defend her.
Nick, who hates fads, goes back and ends up hitting on Heather and taking her back to the apartment. She ends up taking him into his bedroom where they have hot cave sex. The next morning Heather treats Nick rudely and insults Joel on his way out. Nick tries to find out if she has any friends and Heather tells him to call her friend Brandy.
Kate meets for lunch with Leslie and Thorne, and they tell her to confront Heather and stand up for herself. They go to the yogurt store and Heather is impressed by Thorne standing up to her. They end up bonding over the fact that all the men they know are wusses.
Heather and Nick play squash and she beats him soundly, then takes him back to the apartment for more caving. She comes out for beer and to find out why Nick hasn't called Brandy, then goes back for more caving with Nick. Later she leaves but not before telling Nick to finish his dissertation by the weekend. Joel is impressed, but he and Andy point out he's whipped and tell him to man up.
At the shop, Andy ends up talking to a girl and Heather demands to know why he hasn't called Brandy. Andy lies (badly) that he's gay and Heather tells him to make out with the guy at the next table. Andy runs out of the shop.
Joel gets together with Kate for drinks but when he tries to (unwittingly) dump on Kate's new friend, Kate takes it out on him, wanting to know why he thinks all women hate other women then stalking out.
Nick takes Heather to the movies, but she's as rude as always. He finally says he's going out to get popcorn… and runs away. Later, the guys wait outside the yogurt store until Heather gets off the shift, and end up paying a kid to get them yogurt. The kid ends up running away with their money.