When Jon got back upstairs, Sarah was nowhere to be seen. His suspicion was immediately aroused and he checked for the rock, which unsurprisingly had also gone. Jon wondered how Sarah could have known about the magical stone, but that was not important--what was important was to find Sarah and get the rock back before she did too much damage.
Sarah only lived a block away, and while she could be anywhere within a few miles, Jon figured the most likely place she would have gone was home.
Rushing out past his mom, mumbling an incomprehensible explanation, Jon ran the few hundred yards until he was standing on the darkened street outside Sarah's house. There were no lights on at all at the front, so cautiously, he sneaked round the side of the house to the back.
At the back a single upstairs light was showing through drawn curtains. Jon figured it was a good bet that that was Sarah's room. Fortunately for him, there were climbing roses entwined around a wooden frame, just next to the window with the light. Ever so carefully, Jon climbed up the frame until he was level with the window. He picked up a few painful cuts on the way from the thorns, but soon had himself in a position where he could lean over and peak through a gap at the edge of the curtains into the room.
Jon hestitated a few seconds before leaning across. He reassured himself that this was Sarah's house and room and that he wouldn't find himself quickly arrested for peeking at some old lady in her drawers.
With a deep breath, Jon leaned across and looked in the gap. He was relieved to see that it was indeed Sarah's bedroom and slightly embarrassed to see her standing there wearing only her panties and bra. She was looking at herself in the mirror and grasped the rock in her right hand.
Sarah's lips moved, but Jon could not hear what she said through the glass. Then all of a sudden he felt a strange sensation and had to look away. This almost caused him to lose his balance and he held on desperately, trying not to make too much noise.
As the adrenalin subsided, Jon looked back into the room to see what the effect of the wish Sarah had made was. The girl in the room was still clearly Sarah, but now looked about 25 rather than 16. She was turning this way and that in front of the mirror with a satisfied grin on her face. The extra years had given her a little extra height, longer hair and more mature features, but her famous bustline that gave her such control over most of the boys at school had not improved and in fact looked relatively slightly smaller with her extra height.
Sarah seemed to notice this and grabbed the rock from where it was now lying on the bed. She started to mouth words and Jon, wise to his precarious position, closed his eyes for a few seconds. When he reopened them he could only smile at what he saw. Sarah was struggling to remove her bra. It was now much too small for her new breasts gained courtesy of the stone. It obviously had not occurred to her that she could just wish for the clothing to be the right size.
She finally unhooked the bra and her new breasts were unconstrained. To Jon they seemed rather over-large for he slender frame. Sarah looked at them and frowned slightly, hefted them in her hands and shook her head. She grabbed the rock again and made another wish before Jon had a chance to look away. This time however there was nothing forcing him to avert his gaze--the wish had not worked. Sarah looked down at her bust with dismay and tried again. Jon realised what had happened--Sarah had just discovered the hard way two truths about wishing: 1) be specific, 2) wishes cannot be undone.
Sarah seemed to get somewhat frantic as she seemed to be trying to undo her other wishes with no success. Jon wondered how 25 year-old Sarah was going to explain this to her parents, or at school tomorrow. He was tempted to just leave her to it and try to get the rock back later, just so he could enjoy the scenes.
However, just as Jon was about to begin his climb down the framework, he brushed his face again a prickly leaf and could not help himself sneezing. Loudly.