So it’s about regretting not confessing to someone you love.due to that regret(and the lingering attachments he has for sakurai) the black hair guy arrives in the reference room at particular hour even after his death and confessed his feelings.the white hair guy says he is changed and that he no longer had feelings towards the black hair guy which helps the black hair to finally let go of his attachments as sakurai rejected him(something like that).since then the black hair dude doesn’t come anymore as he has finally Rest In Peace.meanwhile, the white hair dude again regrets his actions and hoping the black hair dude would appear again he goes to the reference room during that particular hour.he deems his action (where he couldn’t confess his feelings toward the black hair guy) as a debt and oneday when his debt is cleared he will be able to meet the black hair guy again.
So it’s about regretting not confessing to someone you love.due to that regret(and the lingering attachments he has for sakurai) the black hair guy arrives in the reference room at particular hour even after his death and confessed his feelings.the white hair guy says he is changed and that he no longer had feelings towards the black hair guy which helps the black hair to finally let go of his attachments as sakurai rejected him(something like that).since then the black hair dude doesn’t come anymore as he has finally Rest In Peace.meanwhile, the white hair dude again regrets his actions and hoping the black hair dude would appear again he goes to the reference room during that particular hour.he deems his action (where he couldn’t confess his feelings toward the black hair guy) as a debt and oneday when his debt is cleared he will be able to meet the black hair guy again.
P.s : it’s based on my understanding T_T