When Xia Cha, a 69-year-old widower, falls down the stairs to his death with his grandson Xia Zefang in tow, the last thing anyone expects is for Xia Cha to resurrect in his grandson's body at their funeral.
Ye Haiyuan, the classmate Xia Zefang has been chasing all this time and wants to become a woman and be together with him, has rejected Xia Zefang a few times knowing Xia Zefang wants to be a woman, but Ye Haiyuan is certainly gay (plus some other issues). He comes to the funeral and bumps into a just-resurrected Xia Cha, and has to figure out how to live life with this old man in his grandson's body.
From the novel: Xia Cha, old man in a young man's body, is forced to go to school with Ye Haiyuan and live life normally as Xia Zefang while he's stuck in his body, and interacts with Ye Haiyuan by being the old man he is - taking care of him like he would a grandson. Over time, Ye Haiyuan begins to realise his feelings for Xia Cha and gets used to being cared for by him, only for Xia Cha to "fall in love" with someone else?!