Katie held up their oldest sister, Denise's, bra.
Seeing the bra, Declan said, "You're going to turn into Denise?"
"Yep," said Katie. "I always wanted to be older like her. Since she's a teenager, she gets to stay up late and drive and all kinds of grown up stuff." She smiled. "Plus, she's got boobs."
Katie was about to touch her sister's bra to the medallion, when suddenly she stopped.
"Wait a minute," she said. "This thing works right away, right?"
"Yeah," said Declan.
"Okay. Then maybe I should take my clothes off first so that I don't tear them apart while I'm growing."
"Oh, yeah," said Declan. She was a little surprised at the forethought her sister had just shown. That surprise was quickly replaced by and awkward embarrassment as 9-year-old Katie began to strip naked in front of her. Declan quickly turned her back to Katie to give her privacy.
"What are you doing?" asked Katie, who was now completely naked.
"I shouldn't be looking at you naked. It's... indecent."
"Don't worry about it silly," Katie said. "Little girls can see other little girls naked."
"Could you at least put a bathrobe on or something?" asked Declan, still facing away from Katie.
Katie groaned, "Fine."
Declan heard her sister leave the room. When Katie returned a minute later, she was wearing a too large pink bathrobe. Denise's bathrobe.
"Happy now?" asked Katie.
"Sure," said Declan.
"Alright then, here we go," Katie said and touched the bra to the medallion. "Oooo," she said. "That tingled!"
Immediately, Declan could see her sister growing taller. Katie looked down and watched as her feet grew further away from her.
"Wow," Katie said. "It's really working! This is soooo weird." At that point, she appeared to be a few years older. Under the bath robe, Declan could see the first traces of breasts pushing against the fabric. These mounds continued to expand as Katie entered her teen years. At the same time, her hips widened as her lengthening legs grew curvier. Her face became less childish and began to resemble their sister more and more. Her hair, which originally was brown, was fading to the same natural blonde of Denise's hair. All the while, her body continued to stretch taller.
To 6-year-old Declan, Katie was becoming ever more intimidating with her increased size and age. She was starting to regret giving the medallion to Katie as she began to doubt if Katie would give it back.
When Katie reached 18, the same age as Denise, the changes stopped. Katie was now an exact double for Denise. She examined her body, her sister's body. She was 5'7" tall now. Looking down at her feet again, she said, "Holy crap, look how far away my feet are now."
Hearing herself speaking in Denise's voice, she said,"Hello," as deeply as she could. And then, giggled to hear how mature she sounded.
Noticing her breasts next, she put her hands on them and squeezed.
"Oh, these are wonderful!" said Katie as she enjoyed her new breasts. She looked at Denise's bra and read its size. "And, they're B-cups. Cool."
Declan couldn't help but chuckle at the sight of his older sister's body acting like a little girl. Denise always tried to appear very mature and respectable. He could only imagine her embarrassment if she saw Katie making her look foolish.
After looking herself over for a minute, Katie noticed Declan again. "Awwww," she said. "You look so cute and shrimpy from up here." She put a hand on Declan's head and caressed her hair. "Thank you," she said and bent down to give Declan a big hug. "You're the best brother... er, uh, sister ever."
"Uh, your welcome," said Declan. As she stood there in her much larger sister's warm embrace, she decided that this was a good moment to try to get the medallion back. "So, would you mind letting me put that medallion away now... you know, to keep it safe."
Katie stood up and looked at the medallion again. "Hmmm," she mused. "I don't know. I might want to try this out on someone else first."
"What?" said Declan. "You can't! We can't let anyone find out about this or they'll take it away from us."
Katie thought about her choices for a moment. Would she give the medallion back to Declan, or would she use it again on someone else? Looking down at little Declan, Katie knew that she could do what she wanted without this little girl stopping her. And, additionally, now that she looked like Denise, she could pretend to be her sister. That opened up a lot of possibilities. What would she do?
Eventually, Katie came to a decision and said, "Okay, I am going to..."