A boy of 18 hailing from a noble family in a future world suddenly gets a call from his ancestral home that his grandma is very sick and wants to meet her descendants as if it were their last meeting. She specifically asked for that particular boy and one of his cousins , and their parents obliged them to come. Reluctantly, the boy comes home and sees off his grandmother with his cousins. At the short time he stayed there he grows a crush upon one of his cousins although she is older than him considerably and her parents are looking for bridegroom to marry her off. Before leaving, his granny presents him and the other cousin who was his crush with 2 pieces of heirlooms. The boy gets a wooden box full of random stuffs his late grandfather owned and a ragged old diary that was meant to be delivered to him when he would turn 18 by his grandfather. Confused and slightly bit cringed, the boy soon finds out the mystery behind this diary as he starts to swap body with his grandfather at his 18s lead a double life with him on regular basis. The phenomena gets more problematic as they start to fall in love with 2 different persons in their own timeline as each chooses different lover when they are taking over. The story is about how these 2 manages to lead their double life as normally as possible and avoid the forthcoming family tragedy that is about to come to them. Also how these 2 boys in their adolescence get over their feelings and creates their persona by learning from other's perspective.