Crayon Shin-chan: Springtime with Nohara Shinnosuke

Lin Zhe, a college student from the 21st century, transmigrates into the body of a six-year-old child. He wakes up in a room decorated with Action Mask, then recognizes the Nohara family nameplate and the streets of Kasukabe, confirming that he's in the world of Crayon Shin-chan. Stunned and bewildered by his young reflection in the mirror, he also receives the original owner's memories and learns that he's a transfer student at Futaba Kindergarten. Thus begins his new life in Kasukabe.