Oh man if the grandpa finds out about that night, I'm not sure if he would keel over and die or storm into the office and try to smash the shit out of Takeda.
@manabi I second this, ch. 1 already tells us that the current timeline is farther into the future than us. The flashback timeline definitely isn't WW2, their cars and laptops should be further proof of this. It should be around our time, and the current timeline should be some decades after...