Seokjin, before passing away makes an unbelievable promise to his husband and children, Jungkook and the twins; Jimin and Taehyung. He promised to return one year later on a rainy day. Miraculously, he keeps the promise and reappears before his husband and sons but all his memories have disappeared. Now what will happen to them? What Jungkook and the twins will do with clueless Seokjin?