"Inside Mari" is a Japanese manga series written and illustrated by Shin'ichi Sakamoto. The story follows a high school student named Mari Yoshizumi, who mysteriously finds herself inside the body of a girl named Kyouko. As Mari navigates this new reality, she grapples with the challenges of living someone else's life while trying to uncover the reasons behind her unusual situation. The manga explores themes of identity, consciousness, and the complexities of human relationships. It combines elements of psychological drama and fantasy, offering readers a unique perspective on self-discovery and the impact of one's choices on others.