You've already been changed into a girl. You don't see how your situation could get any worse. The more you think about it, the more you realize how fascinated you are at the idea of walking around as a girl for the day.
With your mind made up, you tear open the package and pull out the underwear. You slip your smooth legs into the white panties. It feels a little strange to have them so snuggly hugging your female crotch. The bra is tricky, but after a few tries you hook it on properly. It fits your B-cup breasts like a glove. It too is white, with a faint embroidered pattern on the cups. The support it gives feels very comfortable, although you know these breasts will still be awkward to deal with for a while, until you've gotten used to them.
You chuckle to yourself at the prospect of getting used to having breasts. It disturbs you and intrigues you at the same time. You chuckle some more, partly to keep your mind from worrying, and partly because of your cute new voice. You sound positively girlish.
You roll the white stockings up your legs. They reach halfway up your calves. You put on the blouse, which is trickier than you expected due to the buttons being on the opposite side. You button it up almost all the way, but you leave the collar open. You won't be going to school, so why be too formal? After you do the cuffs, you proceed to slip into the skirt. It fits perfectly around your waist without the need for a belt, and the zipper disappears into the right side hem. The skirt falls almost to your knees. Finally, you throw the vest over your head and straighten it over the blouse.
You run a hand through your thicker hair, trying to straighten it. You still look a little boyish with its short cut, but for the most part you are unmistakably female.
Now you're finally ready to go and have a talk with the woman. You tear your eyes away from the pretty girl in the mirror and slowly exit the dressing room stall. You feel your breasts swinging ever so slightly with each footstep. Because of your new center of gravity and shorter eye level, you have to concentrate on keeping your balance. In doing so, you inadvertently take smaller steps and move with a bit of a feminine sway.
You catch the clerk's attention quickly. She walks briskly over to you, and you're startled to find that you have to look up to make eye contact.
"You look adorable," she says. "Good choice."
"Thanks," you squeak. You're not used to your new vocal cords yet. "I sort of...fell into it."
"I gather you'll be buying it today?" You see her blatantly size you up, trying to tell if you're wearing the bra under your blouse.
"Yes," you say with a bit of agitation. Nobody's ever stared at you like that before, and now you understand why real girls wouldn't like it. "But I've got a few questions."
"That's what I'm here for," said the brunette.
You ask her if you can ever change back to the way you were, and she allays your fears quickly. She explains that the hangers are under the influence of a magic spell. Any clothes hung on them act as a template. Whoever removes the clothes from the hanger then transforms into a body appropriate for them. The only catch is that the entire wardrobe has to be hung from it, otherwise the hanger will only transform the parts of the body represented by the clothes. This, she explains, is why the bra, panties and stockings were attached to the skirt.
"So if I take the hanger and put all of my old clothes on it, when I remove them, I'll change back to a guy?"
"That's right. Just remember to include your socks and boxers, or else you'll still have a few female parts. The hanger comes free with purchase of the costume."
This all sounds too good to be true. You can change back, just like that? No problem? There had to be a catch. In books where magic was involved, there was always a price to pay.
The woman notices your skepticism. "What, do you think we deliberately trap our customers in alternate forms? That wouldn't be very good for business."
"Sorry, I'm a little new at this." Even now, as a girl in the middle of a strange costume shop, you find it hard to believe that such a thing as magic was responsible for your transformation.
"That's what I'm here for. Is there anything else you'd like to know?"
You can think of at least ten things, easy. For the moment, however, you decide not to bug her with non-critical questions.
"Now," she says, taking your silence as a negative. "Why don't we get you some shoes? Proper girls don't go walking around in their stocking feet."