"What the --" Robert exclaimed. Upset by the bizarre, inexplicable change in his body, he tried to get up, but with his weakened muscles he miscalculated the effort he needed to use and moved up only a few inches off the couch before falling back down.

He tensed his abdominal and thigh muscles to try again, but Jess put her hand on his shoulder to stop him. Her slender arm felt like it pulled him down with the strength of Metro High's Left Tackle. He couldn't move an inch. She looked at him, annoyed, and said, "What happened all of a sudden? We were doing something. Where do you think you're going?" Her hand closed around his flabby biceps. "Hey, what the fuck is this?" she said, squeezing his arm several times. Her fingers compressed his fatty tissue all the way to the bone and yanked it upwards, forcing his hand off her breast.

"I don't -- ouch!" he cried. He tried to pull his arm away but Jess's grip was too tight. He yanked his arm several times, but Jess hardly budged.

Jess wrinkled her nose. "What kind of an arm is this? I thought you were fit!" she said, pulling and pushing on Robert's upper arm and making it jiggle. She pulled her tube up with her free hand to cover back up most of her breast and moved away from him slightly.

"I -- of course I am. You know that!" He tried to tighten the muscles in his chest and abs to prove it, but only made the fatty tissue in his torso shake a little.

"Do I?" Jess asked, rubbing her tight waist. "Yeah, I thought you were pretty fit the last time we were together, before I went away on vacation with my family. It kind of inspired me. I've been working out while I was away, doing crunches and stuff. And all this time you must have just been sitting around watching TV the last two weeks while . I'd sure take my abs over yours any day. And the less said about our chest comparison, the better, you know?" She let go of his arm and massaged his soft chest. "Mine are bigger, of course, but yours are ...."

Robert's face colored red. "You shut up!"

Inside the closet, Amanda wished she could see them, but she could well imagine what was going on. As it was, she was already laughing so hard inside she could hardly keep herself from bursting out in a loud guffaw. She had to leave and creep quietly upstairs for some water to calm herself and stop herself from coughing.

"Well, all right then! I WILL shut up!" She pulled her cardigan around her tube top and zipped it up. "They're all shut up now. And you can finish your homework by yourself!" Jess stood up. "I'm sure Albert Hunt could use some of my company. He might even do MY homework for ME!" She stomped across the room.

"Albert? Wait!" Robert said. He stood up, slowly and tried to follow, but his legs were so weak that he was moving much slower than Jess.

Jess turned and looked at him scornfully. She let him catch up and then held her arm out to keep him away. "You're really pathetic, you know? I don't know WHAT I saw in you." She pushed him and he tumbled into the closet as she skipped up the stairs.

"Where are you going, Jess?" Robert heard Amanda ask.

"Hmmph!" was all she said.

And then he heard Amanda laugh. That was strange.

The whole afternoon had suddenly turned so strange. How had he gotten so weak? Was he sick? Had he gotten some kind of muscle wasting disease? How had it happened so suddenly?

Upstairs, Amanda was wondering what to do. The growth gun worked, obviously. And now she wanted to play with it some more, a lot more. But it was downstairs, while she was upstairs. And Robert was downstairs too.

How was she going to get it? Why didn't Robert just run after Jess? He was so lazy! So worthless. Or had she made him too weak even to try? Grrr! For the moment, she would just have to wait until he came up.

Robert was resting, trying to recover his strength. He was leaning against the closet wall where Jess had shoved him, cushioned by the jackets hanging in front of him, except in one place, where something hard was stuck into his stomach. He fished around the jackets. It was a gun! In Amanda's jacket! He fished it out slowly, worried it might fire.

"Hey Robert, is everything ok?" Amanda called.

"Hey, fuck off and leave me alone" Robert replied in as normal a tone of voice as he could manage. It was quiet upstairs. It worked.

It was a strange gun. No barrel for bullets. A dial on each side. He couldn't read the print in the dark. He pulled a chain that turned on the single bare light bulb. The dial on one side said "Height", with a plus or minus, and on the other it said "Muscle", plus or minus.

Amanda! She had done this to him!

Ha! But now HE had it. And he could "fix" everything, both himself AND Amanda! He turned the muscle dial to plus, all the way to the maximum setting, aimed the gun and fired. Nothing seemed to be happening, so he pulled the trigger harder and kept firing.

Meanwhile, above him upstairs, Amanda was perched at the end of the stairs. Where WAS he? What was he doing down there? If she knew him, now that Jess had stomped out, he was probably in a corner somewhere, jerking off.

Suddenly she felt strange. Not light-headed, but light-bodied, as if her weight was dropping almost to nothing. At the same time her clothing felt constricting. A button on her blouse popped, and then another and another. She looked down in panic -- the whole front of her blouse was open, and -- as was usual for the small-breasted Amanda -- she wasn't wearing her bra, but at least she did have a t-shirt on, although one that was rapidly showing signs of extreme stress. As she looked, her chest was pushing out and her nipples were as erect as they had ever been, like bullets inside her taut tee, ready to fire. Why, she was growing muscle, huge muscles! Robert must have found the gun and was firing it in some random direction!. How stupid could he be, when he should be firing at himself! She cautiously flexed her right bicep and immediately split the sleeve of her blouse.
My god! It was enormous. She must be so powerful! And still she was growing!

What should she do? She needed to get the gun back, before Robert figured out how to use it on himself. On the other hand, she was still growing and she didn't want to move from the spot and miss out. But what if he figured out how to aim and made himself even stronger than she had now become? And what if he reversed the setting and took her new muscle away? No. She couldn't wait. She had to act fast while she was still far stronger than he was.

She ran down the stairs to find Robert and seize the gun back from him.

Inside the closet, Robert heard thundering footsteps. Who could that be? No one in the house made that much noise coming down the stairs. No one, that is, except him.

"Robert, where are you?" Amanda said. "I know you're down here." She looked around. He must still be in the closet. She pulled the door open and pulled him outside. "You've got my gun! Give it back!" She put her hand over the barrel.

He looked at her with horror. His weak, flat chested sister was now bursting with muscle, with rounded shoulders, a thick chest and mound upon mound of beef up and down her arms. She was lifting him in the air as if he weighed nothing. No! That couldn't be! He couldn't let her. As she got ready to take the gun, he twisted the muscle growth dial to negative and fired.

"No you don't!" she cried, snatching the gun away, although he had kept his hand on the trigger and continued to fire for several seconds until she had wrested his hand from it.

"Oooohh," he said faintly, drooping in her arms.

Amanda looked at him, puzzled. "Funny. I don't feel any weaker at all! But what's wrong with you?"

Robert could barely lift his head. "I dunno. I feel ... even worse than ... before."

Amanda put him down, but Robert couldn't even stand. He slumped to the floor.

Amanda laughed. "I can't believe you shot the gun upstairs and made me stronger, instead of restoring your own strength." She flexed her biceps. "Will you look at that!"

Robert could not have been more miserable. "I don't get it. "

"I ought to ... for trying to make me weaker I should ...." Amanda glared at him. "No. I don't want to take this too far. You are my brother. I'll help you. But what happened? Why'd you do this to yourself?"

"I don't know I DID shoot it at myself, the growth ray. But it didn't work. I don't know how it got to you!"

Amanda looked the gun. She set it to growth. "Let me try something." She shot it at Robert. "Look at that! No effect. It's like, once it's been used to make you weaker, it won't work to make you stronger again."

"But look at you!" Robert cried out, as the back of Amanda's shirt ripped. "You've got even stronger again!"

"Yeah. It's like ... once the growth ray hit me once, I attract it. Just as you attracted the shrinking ray you aimed at me. Maybe it's some kind of radiation from the gun that lingers. I wonder how long it lasts." She laughed again. "Poor Robert. For your sake I hope not very long!" She tucked the gun inside the waist of her skirt.

"Don't worry Robert. I wanted to teach you a little lesson, but I don't want to turn you into a weakling for good. I'll keep trying the growth ray on you, and let's hope that the radiation wears off soon."

She tried aiming at Robert briefly again, and the other sleeve of her blouse tore. Robert looked up at her, even more miserable than before. "Ooops. Guess we'll need to wait a bit longer."

Just then the door bell rang. "Oooh, I almost forgot," Amanda said. "I had invited Sharon over to study. Maybe that's her."

"Not Sharon! You'll be with her for hours! And where will that leave me?"

"Don't worry. Maybe she'll figure out a way to help. You know she's even better in science than I am."

"You're not going to tell her about this, are you?"

"Of course! She's my best friend."

The bell rang again, more insistently.