Step three: hypothesis.
Josie absolutely rejected any kind of paranormal explanation. Nope, not possible. Everything that happened had a sound, scientific explanation. So assuming she wasn’t losing her mind, she was left with a scientific possibility. The same girl, the same room, same time. Parallel universe? There she was, back at her parents’ favorite subject. The thesis they’d both spent their careers pursuing: the many-worlds theory. Even Josie’s own attempt to prove the Penrose Interpretation was rooted in the idea that a single particle can exist in two different places at the same time. Penrose theorized that with anything bigger than a dust particle, its multiple states would collapse, so that you only ever saw the particle in one fixed position. Josie loved the simplicity of the Penrose Interpretation—none of the crazy multiple-worlds theories like what her mom had been working on for years. But if Jo was real, and her world was real—two identical particles bigger than a speck of dust existing in different places at the same time—Josie’s science-fair entry was total bunk.
Oops.
Step four: test your hypothesis with an experiment.
That was the step that made Josie’s stomach drop. She looked up at the mirror. There was only one way to find out if that mirror was a portal to a parallel universe.
She’d have to confront the mirror. At exactly 3:59.
3:55 A.M.
Josie sat the floor of her bedroom with her blue-and-white comforter pulled over her shoulders. She’d set her alarm clock for 3:30 a.m. just in case, but it was a needless precaution. There was no way in hell she was getting any sleep that night.
Josie looked at the clock. 3:57. Come on. Why was it that whenever you were waiting for something, time seemed to slow down? It was mocking her and her ridiculous theory.
Was it so ridiculous? If the many-worlds theory was correct, if an infinite number of parallel universes existed, was it such a stretch to assume that at some point in the space-time continuum, two of them would intersect? Josie wasn’t ready to explain exactly how that might happen, but she was certainly prepared to consider it a possibility.
3:58. Josie stood up and let the comforter fall to the floor. If she was right, there was actually another world on the other side of this mirror. A world that she’d been seeing in her dreams each night. A world where a girl who was her but not her lived a life that was hers but not hers.
And if it was true, the theoretical concepts of parallel universes were about to be blown wide open.
Josie could see the reflection of her alarm clock. Any moment now. She held her breath, unable to peel her eyes away from the mirror, as the time hit 3:59.
The image blurred. Josie’s reflection distorted as if she were staring at it through a pool of water. Ripples cascaded across the surface of the mirror, obscuring her reflection entirely, then dissipated. The image resharpened and Josie found that she was staring at her own face, her own eyes once more. Only the girl in the reflection had blond highlights, bright and shiny where Josie’s hair was a duller blond, and the girl in the reflection wore a denim pencil skirt and a red gingham tank top, while Josie was in her shortie pajamas.
Not a reflection.
Josie stared at the girl. The girl stared back.
This was Jo. The girl from Josie’s dreams.
Neither said a word but Josie could tell by the look on Jo’s face that she was excited too. They’d seen the same thing, come to the same conclusion, on opposite sides of the mirror. The girl held up her hand, reaching out to touch the mirror, and Josie did the same. The surface rippled like a pebble dropping into a pond, and instead of a hard surface, the glass was soft and liquid. It was denser than water, though, and as Josie pushed her hand into the substance beyond the edge of the mirror frame, it felt like she was pressing her hand into a tub of pudding. Josie wiggled her fingers in the substance and the image distorted. It wasn’t warm or cold, just spongy and thick. Jo did the same, reaching her hand into the expanse of the mirror.
Then Josie felt it. She was touching Jo’s flesh. Palm to palm.
Josie stared at her hand. She could feel the warmth of Jo’s palm. She was awake, no bones about it. This was real. This was really happening.
She looked up and met the other girl’s eyes. “Jo?”
Jo cocked her head to the side, as if she couldn’t quite understand what Josie said, then her eyes widened. She nodded. Then her lips moved, slowly. Josie couldn’t hear her words; her voice was just a muffled sound through the mirror. Jo repeated it, speaking even slower. Josie could just read her lips.
“Who are you?”
Josie opened her mouth to respond, but the image blurred again. Jo pulled her hand away. Josie did the same, just in time. The image in the mirror rippled, distorting Jo’s face in a squiggly mass of waves, then resolidified until all Josie could see was the pale, panting image of her own face in the mirror.
FIFTEEN