Tsuisou no Augment

Kawashima Hideya is an 80-year-old man who has lived an unsatisfying life. Having lost sight of the purpose in living, he finally decides to commit suicide. He had wished to return to his youthful days for a second chance at life. Just before he sliced his own throat, he heard a little girl's voice - "I'll grant that wish". To his surprise Hideya woke up 60 years in the past, reborn into his teenager body. As it turns out, the one who called out to him and granted his wish was a shinigami...