I Found the Future Dark King Beyond the MirrorEpisode 3

Ivy accidentally travels through a magical mirror and meets Lucien, a cursed prince imprisoned in a forbidden realm. She becomes the only person to show him kindness and gives him hope. Years later, Ivy loses her memories, while Lucien grows into the feared Dark King. When the mirror draws Ivy back into his world, she discovers that the lonely boy she once saved has spent years waiting for her—and will risk everything to keep her by his side.