A Gift From My Enemy: English Version

A story about a lonely girl who really loves biology and all about science. She finds a good boy as her best friend. They have a wonderful journey in another world dimension. But, her best friend is sick, then how can she finds him healthy in the school. This is a story about waiting, self-sacrifice and true love. What is the journey about? Who is a person who has the same face with her best friend? What is the reaction of the girl?