Steins;Gate: Volume 3

Okabe Rintaro - or simply Okarin - is a young student who still lives in a world of childhood fantasies. But when he accidentally invents a time machine capable of sending messages to the past, his life changes completely.
Okabe continues to go back in time over and over again to save Mayuri's life. But if he manages to do this and return to the original timeline, instead of Mayuri, Kurisu Makise will die. Okabe has to choose who to sacrifice...
The conclusion of the world-famous science fiction story.