“Oh, what?” said Sarah's old body, a bit startled and nervous for some reason. “This... uh... this thing here? It's... oh, it's nothing, Sarah.”
Roy had a sickening suspicion as to her evasiveness about the device in her hands. He decided to test out his hypothesis.
“If it's nothing, please let me see it,” he said. “It could be something of mine – that I lost recently and have been looking for.”
“Oh, it's definitely mine,” said Sarah's old body. “Trust me, Sarah. This is mine and not... I mean, I'll help you and Jack look for whatever it is that you lost... but... well, this is definitely mine and... belongs to me... so...”
“...So what is it?” pressed Roy.
“It's... uh... it's a personal thing,” stuttered Sarah's body. “Just a... it's an experiment. Just a little... gadget I've been building... in my spare time... and... it's not finished yet... so... I guess I really shouldn't... y'know, I'll tell you all about it and show it off when it's done... but... still have some... there's still a few bugs... in the system, y'know?”
Feeling reasonably certain Sarah now knew exactly what the device was, Roy decided to show his hand.
“It's from another dimension, isn't it, Roy?” he said.
“What?” answered Sarah's body.
“It was given to you by... an extra-dimensional clone of yourself,” continued Roy. “From another reality. And it can...”
“Were you spying on me?!?” cried Sarah's body.
“No,” laughed Roy. “I... well the truth is more than a little awkward. I am you. I'm Roy Milford.”
“What?” said Sarah's body, scratching her short, masculine hair in confusion.
“That device was given to me,” said Roy. “And I... well, I tested it on you. It switched us around. You're the real Sarah – I'm the real Roy.”
Sarah's body shot Roy a disbelieving look of incredulity.
“How else would I know all of this?” said Roy. “And just look at us – I mean look closely. I'm a guy... and you're a girl! I know you think you're really Roy Milford and I'm Sarah Howard. But look at us: you have breasts and I don't. Yet, I'm the one wearing a bra... doesn't that seem weird to you?”