His grand-father is the head priest of a shrine and he helps him at the shrine when he has a day off from school.
His grand-father feels responsible that Haruto is now helping at the shrine when he has a day off, because when Haruto was a kid he told a lie that he would be late because of lessons. The reason he actually stayed longer at school was because he wanted to burry a time capsule with his friends, but because of the rain they gave up. Also because of the rain his grand-father went to pick him up but when he could't find Haruto he left and on the way back his grand-father got in a traffic accident. Because of that Haruto feels responsible for the injuries and now helps out at the shrine. At least that is what his grand-father thinks. He actually works there on his own free will. When he was younger, he actually admired the work his grand-father did.