Dead End Reloaded

An aloof young man will reset the world with a young girl he meets by fate. A futuristic world where particles related to time and space have been discovered. An aloof and remarkable soldier who lived through the third world war, Hazama Yuuhi, joins the genius scientist Oshidori Keina for a secret experiment. Directly following, Yuuhi and Keina lose their lives to a mysterious attacker. After waking up again, he notices he has traveled back to a time before the the start of the experiment. In the midst of their experience with the death looping phenomena, his bond with Keina gradually grows stronger as they continue to unravel the mysteries before them. Will Yuuhi be able to save Keina from the despairs of death and prevent the future from being thrown into chaos? (Source: HJ Bunko, translated)