A period of grudges and hatreds separated by six hundred years, the promise made by the three of them when they were young, until there is no way back, the immortals and demons are separated. When it comes to the end, do you still remember it? "Do you still remember what you promised me?" Thousands of years later, you can still think back on it, but the persistence you once had will eventually turn into tears. "I am not her. She has been dead for more than six hundred years. Even if she is reincarnated, I am not her after all, am I?" Is it love or hate? Where should the past love go?