Start with Classic Old Dramas

"When you grow up, who will you find as your wife?" "You!" "Okay?" "Okay!" Eighteen years ago, a little girl shyly and bravely asked the little boy this question. The little boy replied without hesitation, "You!" Eighteen years later, the little girl back then has become a singing queen, while the little boy back then has disappeared into the public eye. Until a soul from a parallel world became that little boy.