[The title and blurb are provisional, but the core premise will stay the same.]
After losing both his parents, little Natsume spends his days being passed from one relative's home to another.
One day, a man in a black coat takes him away from his relatives.
His new home isn't warm and welcoming. Instead, it's filled with the stench of blood and gunpowder.
Little Natsume returns to the day before he was taken away.
If only he'd discovered this ability sooner, he could have saved his parents. That's what young Natsume thinks.
An unwelcome guest comes to Natsume's home.
A white-faced bun threatens him furiously: "Hand over the Book of Friends! Or I'll eat you!"
The very next second, after making its threat, time rewinds.
White-faced bun: "Hand over the Book of Friends!"
Time rewinds again.
After the same scene repeats many times, the white-faced bun says weakly, "Hand over the Book of Friends..."
Smack, time rewinds again.
The white-faced bun has run out of strength and options. "Hand over the Book of Friends... Never mind, you can keep it."
Theme: Sooner or later, you'll encounter that ray of light. It may come early or late.