I'm far from fat, but her using me as a sounding board on this topic is like me complaining to a blind woman that I have to wear contacts.

"I am so fat. I totally am! And I chowed at lunch. But whatever. As long as I'm not a fat cow in my wedding dress…" she says, finishing her last spoonful of yogurt and tossing the cup into the trash. "Just tell me I have plenty of time to lose weight before the wedding."

"You have plenty of time," I say.

And I have plenty of time before the wedding to stop thinking about the fact that I had sex with your husband-to-be.

"I better rein it in, you know, or else I'm gonna have to shop here." Darcy points at the plus-size section without checking to see if any larger women are within earshot.

I tell her not to be ridiculous.

"So anyway," she says, as we ride the escalator up to the second floor,

"Claire was saying that we're getting too old for bikinis. That one-pieces are classier. What do you think of that?" Her expression and tone make it clear what she thinks of Claire's view on swimwear.

"I don't think there are precise age limits on bikinis," I say. Claire is full of exhausting rules; she once told me that black ink should only be used for sympathy notes.

"Ex-act-ly! That's what I told her… Besides, she's probably just saying that because she looks kind of bad in a bikini, don't you think?"

I nod. Claire works out religiously and hasn't touched fried food in years, but she is destined to be lumpy. She is redeemed, however, by impeccable grooming and expensive clothing. She'll show up at the beach in a three-hundred-dollar one-piece with a matching sarong, a fancy hat, and designer glasses and it will go a long way toward disguising an extra roll around her waist.

We make our way around the floor, searching the racks for acceptable suits. At one point, I notice that we have both selected a basic black Anne Klein bikini. If we both end up wanting it, Darcy will either insist that she found it first or she'll say that we can get the same one. Then she will proceed to look better in it all summer. No, thanks.

I am reminded of the time that she, Annalise, and I went shopping for backpacks the week before we started the fourth grade. We all spotted the same bag right away. It was purple with silver stars on the outside pocket-way cooler than the other bags. Annalise suggested that we get the same one and Darcy said no, that it was way too babyish to match. Matching was for third-graders.

So we rock-paper-scissored for it. I went with the rock (which I have found to be a winner more than its share of the time). I pounded my jubilant fist over their extended scissor fingers and swept my purple book bag into our shared cart. Annalise balked, whining that we knew purple was her favorite color. "I thought you liked red better, Rachel!"

Annalise was no match for me. I simply told her yes, I did prefer red, but as she could plainly see, there were no red bags. So Annalise settled for a yellow one with a smiley face on the pocket. Darcy agonized over the remaining choices and finally told us that she was going to sleep on the decision and come back with her mom the next day. I forgot about Darcy's bag choice until the first day of school. When I got to the bus stop, there stood Darcy with a purple bag just like mine.

I pointed at it, incredulous. "You got my bag."

"I know," Darcy said. "I decided I wanted it. Who cares if we match?"

Hadn't she been the one to say that matching was babyish?

"I care," I said, feeling the rage grow inside me.

Darcy rolled her eyes and smacked her gum. "Oh, Rachel, like it matters. It's just a bag after all."

Annalise was upset too, for her own reasons. "How come you two get to be twins and I'm left out? My bag is gay."

Darcy and I ignored her.

"But you said we shouldn't match," I accused Darcy, as the bus pulled around the corner and screeched to a stop in front of us.

"Did I?" she said, fingering her stiff, feathered hair, freshly sprayed with several layers of Breck. "Well, who cares?"

Darcy used "who cares" (later replaced by "whatever") as the ultimate passive-aggressive response. I didn't recognize her tactic as such at the time; I only knew that she always managed to get her way and make me feel stupid if I fought back.

We boarded the bus, Darcy first. She sat down and I sat behind her, still furious. I watched Annalise hesitate and then sit with me, recognizing that I had right on my side. The whole purple backpack issue could have escalated into a full-fledged fight, but I refused to let Darcy's betrayal ruin the first day of school. It wasn't worth going to battle with her. The end result was seldom satisfying.

I covertly replace the Anne Klein suit on the rack as we make our way to the long line for the dressing rooms. When one becomes available, Darcy decides that we should share a room to save time. She strips down to her black thong and matching lace bra, contemplating which suit she should try on first. I steal a look at her in the mirror. Her body is even better than it was last summer. Her long limbs are perfectly toned from her wedding workout regimen, her skin already bronzed by routine applications of tanning cream and an occasional trip to the tanning beds.

I think of Dex. Surely he compared our bodies after (or even during, since he "wasn't that drunk") our night together. Mine isn't nearly as good. I am shorter, softer, whiter. And even though my boobs are bigger, hers are better. They are perkier, with the ideal nipple-to-areola-to-breast ratio.

"Stop looking at my fat!" Darcy squeals, catching my glance in the mirror.

Now I am forced to compliment her. "You're not fat, Darce. You look great. I can tell you've been working out."

"You can? What body part has improved?" Darcy likes her praise to be specific.

"Just everywhere. Your legs look thin-good." That is all she is getting from me.

She studies her legs, frowning at the reflection.

I undress, noting my own cotton underwear and nonmatching, slightly dingier cotton bra. I quickly try on my first suit, a navy-and-white tankini, revealing two inches of midriff. It is a compromise between Claire's one-piece edict and Darcy's preference for bikinis.

"Omigod! That looks so awesome on you! You gotta get it!" Darcy says. "Are you getting it?"

"I guess so," I say. It doesn't look awesome, but it's not bad. I have studied enough magazine articles about suits and body flaws over the years to know which suits will look decent on me. This one passes.

Darcy puts on a tiny black bikini with a triangular top and bare coverage in the bottom. She looks straight-up hot. "You like?"

"It's good," I say, thinking that Dex will love it.

"Should I get it?"

I tell her to try the others on before making a decision. She obeys, taking the next one off the hanger. Of course, every suit looks amazing on her. She falls into none of those categories of body flaws in the magazines. After much discussion, I settle on the tankini and Darcy decides on three tiny bikinis-one red, one black, and one nude-colored number that is going to make her look naked from any kind of distance.

As we go to pay for our suits, Darcy grabs my arm. "Oh! Shit! I almost forgot to tell you!"

"What?" I ask, unnerved by her sudden outburst, even though I know she isn't going to say, "I forgot to tell you that I know you slept with Dex!"

"Marcus likes you!" We might as well be in the tenth grade, from her tone and use of the word "likes."

I am intentionally obtuse. "I like him too," I say. "He's a nice guy." And a hell of an alibi.

"No, silly. I mean, he likes you. You must've done a good job at the party because he called Dex and got your number. I think he's going to ask you out for this weekend. Of course, I wanted it to be a double date, but Marcus said no, he doesn't want witnesses." She drops her bikinis onto the counter and fumbles in her purse for her wallet.

"He got my number from Dex?" I ask, thinking that this is quite a development.

"Yeah. Dex was cute when he told me about it. He was…" She looks up, searching for the right word. "Sort of protective of you."

"What do you mean by 'protective'?" I ask, way more interested in Dex's role in this exchange than in Marcus's intentions.

"Well, he gave Marcus the number, but when he got off the phone he asked me all these questions, like were you seeing anyone and did I think you would like Marcus. And you know, was he smart enough for you. Stuff like that. It was really cute."

I digest this information as the store clerk rings up Darcy's bikinis.

"So what did you tell him?"

"I just said that you were totally single, and that of course you'd be into Marcus. He's such a sweetie. Don't you think?"

I shrug. Marcus moved to New York from San Francisco only a few months ago. I know very little about him, except that he and Dex became friends at Georgetown, where Marcus's claim to fame was graduating dead last. Apparently Marcus never went to class and got high all the time. The most infamous story is that he overslept on the day of his statistics final exam, showed up twenty minutes late only to discover that he had thrown his remote control into his backpack instead of his calculator.

I haven't yet determined whether he is a free spirit or simply a buffoon.

"So are you psyched? If you get a date in with him before our share starts, you will have dibs on him over Claire and Hillary."

I laugh and shake my head.

"Seriously." Darcy signs her receipt and flashes a smile at the clerk. "Claire would love to sink her nails in him."