“It’s probably in the book,” he muttered, eyeing the shelf where the massive Nelson Mathematics 7 textbook sat like a brick. It was 500 pages of dense graphs, word problems about train speeds, and the haunting, glossy photo of a teenager looking far too happy to be calculating the volume of a cylinder.

He worked through the problem, but something felt off. In the PDF, next to the answer box, a faint, penciled note read: "Mr. Jensen’s class: The answer in the back is wrong. It’s 392, not 376. Trust the formula."

Leo blinked. He knew that handwriting. It was his own—from a future he hadn't lived yet.

The ghost in the PDF—a former student named Maya, according to the handwriting—had saved him.

He clicked.

At 2:00 AM, he finished the last question. He was about to close the PDF when he noticed the final page. The moving, chaotic doodles stopped. In the bottom corner, written in neat, fresh pencil that didn’t appear in the scan's shadow, were three new words:

Leo didn't care. He found Chapter 5: Measurement. There it was, Question 14: "A rectangular prism has a length of 12 cm, a width of 8 cm, and a height of 5 cm. Calculate the total surface area."

The file was massive—a ghost in the machine. When it opened, it wasn't a clean scan. The pages were crooked, shadows falling across the margins like folded corners. Some pages were coffee-stained. On page 47, someone had doodled a rocket ship blasting off from the graph of y = 2x + 1 .

But the textbook was also a thousand miles away, buried in his family’s moving truck.

A dozen links bloomed. Most were dead ends: corrupted files, websites that demanded his mother’s credit card, or forums where people argued about Common Core. Then, a strange, plain page appeared. No ads. No logos. Just a single download button.