该剧以"平行世界"为背景,上帝把恶魔释放到了人间,恶魔打开了平行世界的大门。如果另一个世界有比"我"生活得更好的"我",你会跟他改变你的生活吗?面对恶魔抛出的这些问题,欲关上平行世界之门的理科型大韩帝国皇帝李坤,和为了守护爱情的文科型韩国刑警郑泰乙,通过跨世界互助演绎出时而激动、时而酸涩,层次不同的罗曼史。The story is about a Korean emperor Lee Gon (Lee Min-ho) who tries to close the doors to a parallel world which was opened by demons who were unleashed by a deity into the human world, and a detective Jung Tae Eul (Kim Go-eun) who tries to protect the people and the one she loves.