The giant girls smile at each other as if to confirm their intentions. Jess walks over to her diminutive sister, and squats down in front of her. Stood up, Katie was looking straight at Jess' crotch in her shorts, before the giant sister snapped Katie out of this trance. "Ahem, my face is up here! Enjoying the view my itty bitty sis?" she says, with a wide grin. Katie's face blushed red, she didn't even know what she was doing. Jess held her funger underneath Katie's chin so that she was looking at her. "Now I really am going to be the big sister!" Jess said with an evil smile.
She stood up to her full height, and turned the gun on herself after flicking a switch and turning a dial. A flash of light came and went, and before long, everybody was transfixed on Jess' body. "Ohhh!" she screamed. "It's happening!". Katie was genuinly frightened at what would happen now. She thought she was shrinking again, but noticed that only Jess was growing. "Great..." she thought. Her being shrunken to smaller than a midget was bad enough, but now her younger sister was going to be a giant! Janet looked at Jess who overtook her own height within just a few seconds, before looking down at Katie who's jaw was dropped, unable to take her eyes off her expanding sister.
As Jess grew, she stood as tall as she possibly could, just to make Katie feel even smaller. She rubbed her body as she grew, loving the sensation of becoming bigger than she ever dreamed of being. From her toes, through her legs, past her crotch and belly, and her breasts, all the way up to her head, she could feel every part of herself expanding. And it was great. "Oh yes!" she screamed, in an almost orgasmic way. "Bigger! Keep growing bigger!" she yelled to nobody in particular.
She eventually stopped growing, and looked down at her older sister, and her best friend. Janet was now level with Jess' expanded boobs, and Katie was barely half way towards her younger sisters knee. Katie looked at Jess' feet, and was stunned at how big they had grown. Before, they would really hurt if she was kicked with one, now it looked as though a mid-strength blow would probably kill her! She followed the legs up, examining every bit of her sisters body, before finally gazing her in the eyes again. She was around 7'4" now, and would have to duck slightly to get through a door frame.
Janet was the first to break the silence. "Wow, Jess, you're a giant!". "Thanks" Jess said, smoothly and calmly, with a slight chuckle. She looked back down at her shrunken sister, wondering what to do next.