At a high school graduation ceremony, a white chrysanthemum flower is left on top of an empty, vacant seat amongst the students receiving their diploma. The white chrysanthemum flower is forever engraved in Ian’s memories, a period to his last day of high school. Ten years later, Ian is working as an agent for the resistance against a giant corporation that is a threat to humanity and he is killed in an explosion during a secret operation. Instead of being greeted by the reaper, Ian opens his eyes, only to find himself 10 years back into the past in high school. The only thing Ian can remember is the white chrysanthemum flower he saw on the last day of high school. The grieving pain is the only feeling Ian remembers, nothing from his past, his friends, the accident, every memory has slipped away. Is it a side effect of returning to the past? Or is it some mysteries power intervening? Will Ian be able to learn why he returned to the past and change the course of his past and future?