The main character, “Kyosuke Suo”, who was living an ordinary life, was involved in an accident one day and was supposed to be at the end of his life, but his life was saved by a girl named Setsuna.
Kyosuke decides to let him stay in his room to return the favor at the moment when he says he has no place to go back to, but after that, he begins to have strange dreams and is struck by an alien power.
He will awaken to the “power to go back into the past.”
A series of disappearances that occur frequently in the town begin to involve the protagonist’s loved ones.
The protagonist tries to solve this problem by using an alien power, but his body collapses with unbearable pain.
…Every time the pocket watch in her hand turns back, the girl in her dreams sheds tears.