Be Kind Rewind

Jim had rewound the video several times over. It showed the last few moments of him being in his own body before he switched with Helen. He was hoping he’d see something that would tell him how she managed to do this. If he could figure it out, he might be able to figure out a way to reverse it. But there didn’t seem to be any clues. One minute he was standing there next to her, then the swap happened without a beat dropping. He rewound yet again. What was he missing?