You watch from the kitchen window as Emily makes her way towards your other sister, Tina. You then turn around and start making a sandwich for lunch.
Tina was busy in the backyard sunbathing herself. The 15 year old spent a lot of time on her body to make it as attractive as possible. From doing an hour of cardio every morning to making sure she didn't eat to many sweets, she had, for all accounts and purposes, a perfect body. Nice, perky breasts, a trim waistline with a few abs sticking out. She even had a pretty sizable booty. Not surprisingly, Tina was the object of desire for the majority of guys at her school, something she loved very much.
Tina smiled, as she laid there in a lawn chair, soaking up as much sun as she could. She was wearing only her bra and panties, with a pair of sunglasses over her eyes for good measure. She was just about to drift off to sleep, when Tina could sense the outline of someone walking up behind her. The person's shadow was fairly large, so Tina could think of only one person.
"Matt," she said simply. "Get the hell out of my way. Can't you see I'm sunbathing here?" A few seconds later, the shadow disappeared, without saying a word. Tina sighed loudly, then closed her eyes again, determined to take a nap. "Stupid brother," she muttered to herself.
It wasn't long when the shadow returned, followed by her little sister's laughter. The shadow blocked out the sun once more, so Tina sat up, annoyed. She turned around to face her brother, when the large face of Emily filled her vision. The 10 year old was bent over, her hands on her legs for support, peering down at her older sister, a big grin on her face.
"Emily?" Tina said, not believing what she was seeing. Tina stood up to face her now massive sister, as Emily stood up to her full height. Tina gasped, as the top of her head barely reached her younger sister's bellybutton now. Emily had to be close to nine feet tall now. She was still fully clothed, as her clothes had apparently grown along with her. The only question was: how the hell did her 10 year old sister grow to this size to begin with?
"Emily? Is that really you?"
The younger sister nodded her head. "Guess I'm the bigger sister now, huh?"
"How did this happen?" Tina asked, a little intrigued.
Emily just stood there, a slight smile on her face, seeming to drift off for a moment. "Hey, wanna play?" she replied, probably in an effort to change the subject.
"Oh, I don't know," Tina said, starting to back up a little bit, eyeing the back door of the house. "Don't you think I'm a little too small to play with now? I mean, you probably want to play with kids your own age, right?"
Without warning, Emily bent down and grabbed Tina by both arms, hoisting her into the air. The 15 year old screamed, shocked at the strength of her younger sister now. She struggled to break the grip Emily had on her, only to give up when she couldn't get free. Above her, the little girl laughed. In desperation, Tina began kicking, succeeding in kicking Emily's shins and legs several times before the 10 year old let her go, tossing her roughly to the ground.
"Why did you do that?!" Emily asked angrily, looking down at the places she had been kicked, to find bruises starting to form. "I just wanted to play with you!" Emily brought something that looked like an oversized water pistol out of her back pocket and started messing with the controls.
"W-What's that?" Tina asked, backing up once more.
"Oh, you'll see," Emily replied cryptically, before she...