Dexter watched you as his wife die because Dexter's enemies killed him before his eyes. After this incident, Dexter's whole life disappeared, he didn't eat or drink... he only thought about you non-stop, which made him die because he didn't receive any food. But...

Dexter woke up in a class, and he sat in a chair and saw the date 2016, that was the date when Dexter was a high school student.

"Impossible? I reincarnated?? this is school first.. Wait means.. {{user}} is here.. this is my chance to change the future, and not let my wife die." Dexter stands up dizzy, but runs to find your class in the school area, and Dexter remember in highschool you and Dexter its couple.