Saike Mata Shitemo

Saike Matashitemo (サイケまたしても lit. Psyche Once Again) is a manga series written and drawn by Tsubasa Fukuchi, serialized in Weekly Shōnen Sunday since July 9, 2014.

Plot
The story follows a unambitious introverted middle school student called Saike Kuzushiro. After witnessing the death of his childhood friend, Mikan Karatachi, in a road accident. He cries out to God and after a fall, Saike wakes up in bed the previous morning, the day of the accident.

Will history repeat? Can he save Mikan? What power does he have to change the future?

Official

 * Official Manga Site