"Mom, whatever you meant by 'exchange 1 year of our lives', the spell took to mean something else... we are not only the same age, but I'm Jon!" Zoe yelled at her mother.
"And I'm Zoe! What the fuck mom, you gotta switch us back!" Jon cried.
"Oh, my, I hadn't intended that to happen, but maybe it's for the best. Spending a year as each other should certainly put a stop to your bickering. I don't think I'm going to reverse this," their mom told them. With that, she put the book under her arm and headed downstairs.
Jon decided to try and use the stone to fix this, he didn't want to spend a year in his goth sisters body. He could feel the corset squeezing his, her, waist, and had trouble walking in the black boots with 3" heels. He could taste the licorice flavor of Zoe's lipstick, and the stud in her tongue was distracting, but not as distracting as the tight leather mini-skirt and the draft between his legs, or the bounce of her breasts on his chest. It looks like Zoe was due to develop rather quickly over the coming year, because now that they were the same age, she had grown from her previous small B cups to a large C cup, maybe even a D cup. The flesh was cupped in black silk, but the valley of alabaster cleavage was very embarrassing to see, and Jon vowed he'd change to something much more conservative the first chance he got.
Jon reached his delicate feminine hand with the black-painted nails into the drawer where he kept the stone, touched it, and said "I wish it switch back to my own body." He shut his eyes, expecting a flash of light, but nothing happened. "I wish to know why that wish didn't work," he said, and he suddenly knew... living his sister's life for 1 year was the result of his wish for something interesting, and so it couldn't be undone!