In the third year of high school, I exchanged bodies with Yukinoshita

At the end of midsummer, during a lunch break, I exchanged bodies with a stranger from a parallel universe.
My name is Zuo Yu. I’m a senior high school student. I’m enjoying the high school life with five days off and eleven days off, and living a colorful youth on the black and white test papers.
The person who exchanged bodies with me was called Yukinoshita Yukino. She was a freshman in high school and lived a busy high school life. There was no trace of her in the colorful high school.
The two people were originally from parallel time and space, living parallel lives that never intersected, but they began to intersect because of the body exchange.