After entering the palace, Xu Jingyi discovered that Emperor Xiao Rui, who was rumored to be majestic and stern, turned out to be a stubborn-mouthed, pure, and insomnia-prone "wife-slave". Because of a wrongly called name, he bitterly practiced spinning tops, secretly visited the bedchamber at night, and frantically checked household registers, all just to remember everything about her. A pet name "Erdan" triggers a series of absurd palace misunderstandings, and also allows this bickering pair to finally recognize each other amidst bickering and heartbeats.