Hello World

In Kyoto in 2027, Naomi Katagaki lives a quiet, isolated life and cannot bring himself to approach his classmate Ruri Ichigyou despite their shared love of books. Then a mysterious man appears and claims to be Naomi himself ten years in the future, carrying a warning: shortly after the two begin dating, Ruri will suffer a tragic accident.

Young Naomi follows his future self's instructions, learning how to grow closer to Ruri while altering the chain of events leading toward the disaster. The world surrounding them is not as simple as it appears, however, and knowing the future is not the same as knowing the whole truth. Every change saves one moment while opening a new question about reality and memory, until Naomi must understand whether the man who came to save Ruri can accept any future that does not match the one he wants.