Dreamlike, Picturesque

I would like to be a close friend in this life, and I would like to be a couple in the next life. Three love affairs that have not been recorded in history books. Today, three hundred years later, the three characters embarked on a long and arduous journey to find this period of history in the afterlife, in order to know the ending of that period of history. Can they find it? Can the vow made three hundred years ago be fulfilled in this life?