The last message Ye Xuan received from his mother contained six words.
Don’t forget to eat something warm.
He read it outside a convenience store in Hangzhou, standing beneath an awning that failed to keep the rain off his shoes. His phone battery showed nine percent. In his pocket were twenty-three yuan, a bus card, and a key that no longer opened anything.
That morning, the landlord had finally cleared his brother’s room. Ye Ming had disappeared three years earlier, leaving behind engineering books and a notebook. Their mother still paid for the room, though nobody believed she could afford it. Ye Xuan found one sentence on its last written page:
If the result is impossible, check what you assumed.
Ye Xuan put the notebook in his bag and crossed toward the bus stop. Nearby, a woman carried groceries while a little boy in a yellow raincoat splashed through puddles. A plastic dinosaur fell from her bag.
The boy chased it.
A delivery truck entered the intersection as the signal changed. Its horn sounded once, long and desperate.
Ye Xuan saw the truck, the child, and the distance between them. He did not see a way for all three to occupy the same stretch of road and survive.
He ran anyway.
His hand caught the back of the yellow raincoat. He pulled, twisted, and threw the child toward the woman. Something struck his shoulder with the force of a collapsing wall.
The street turned sideways.
Then even the rain was gone.
The first thing he heard was an argument in English.
Ye Xuan opened his eyes to a ceiling stained by an old leak. Sunlight crossed the wall in a narrow rectangle. Someone downstairs was frying onions.
His hands were different.
He stumbled to the mirror.
A Chinese boy looked back at him. Eighteen, perhaps nineteen. Black hair refusing to lie flat. A narrow face. A faint scar near the left jaw.
Almost him.
Not him.
On the desk lay a student identification card.
YE XUAN — HUDSON POLYTECHNIC INSTITUTE.
Below the name was a New York address.
He checked the date on the phone beside it. November 2026. He checked again, as though the month might change out of embarrassment.
His mother’s number was not in the contacts. Neither was his brother’s.
Ye Xuan stared at the screen.
The same unfamiliar reality appeared everywhere. This New York had people who could fly, yet its rent notices looked painfully familiar.
A knock rattled the door.
“Xiao Ye?” an older woman called in Mandarin. “If you’re awake, answer me. I heard you fall.”
“I’m fine,” he said automatically.
“You never sound fine when you say that.”
Her footsteps retreated. Ye Xuan sat down and pressed both palms against his eyes.
He wanted to scream.
Instead, he opened the nearest book, a thick volume on structural mechanics. He read every chapter, exercise and appendix until his eyes burned.
When he turned the final page, something changed.
There was no voice in his head. No luminous screen announced a blessing.
The book simply became clear. Every theorem, every hidden assumption, every proof fit together without effort.
Not remembered. Understood.
He could see the structure of every argument, the assumptions beneath every equation, the places where one result depended on another. An exercise he had struggled with twenty minutes earlier now seemed as transparent as a glass of water.
He seized a pencil and wrote out its solution.
He tried another approach, then a third, which used a different constraint and exposed an approximation the textbook had treated too casually.
His hand stopped.
He checked the calculation twice. The reasoning held.
He had not merely learned what the author knew. He had found something the author had not written.
Yet he still could not predict when the bent shelf above his desk would fail without measuring its brackets. That limitation reassured him.
Understanding had arrived in an instant. The missing measurements had not.
He took another book from the shelf, this one on electromagnetism, and opened it halfway through. He read three pages. Nothing happened.
He turned to the last page without reading the rest.
Nothing.
He laughed once. It sounded close to a sob.
His brother had always told him to read the whole chapter.
A low boom drew him to the window. Above the avenue, a figure in a dark uniform drifted through the air, carrying a broken traffic light in one hand.
People below raised their phones. Nobody ran.
The figure landed, and the street resumed its noise. Ye Xuan watched the crowd accept the impossible as part of an ordinary commute.
Ye Xuan closed the textbook.
For the first time since waking, he felt something stronger than terror.
He wanted to understand.
Then his borrowed phone vibrated.
A message appeared from an unknown number.
If you remember what happened at the waterfront, do not tell the police before we speak.
Ye Xuan read it twice.
He had been in this world for less than a day.
Someone here already believed he knew a secret.