Su Wan, a modern-day viewer, transmigrates into the world of Ruyi's Royal Love in the Palace as the low-ranking Concubine Su, who can barely even get a glimpse of the emperor. Knowing how the story unfolds, she feels sorry for Jinzong, who gives everything for Wei Yanwan only to meet a tragic end. She despises Wei Yanwan's scheming cruelty and is deeply opposed to the imperial harem's system of sexual consorts.
To avoid being summoned to the emperor's bed, Su Wan draws on her modern knowledge of pharmacology to concoct medicines and cleverly fool her way out of it. In the process, she repeatedly crosses paths with Jinzong, who has been on her mind. As they grow closer, she discovers that beneath a gentleness much like the character's in the show, Jinzong conceals a shocking secret: he is not actually a eunuch.
On one side is the perilous struggle in the imperial harem, where Wei Yanwan's ambition grows by the day and she repeatedly targets Su Wan, who is unfavored yet strangely "well-behaved." On the other is the affection quietly growing between Su Wan and Jinzong. They must hide their respective secrets, Su Wan's identity as someone who transmigrated and Jinzong's true identity as a man, while protecting each other in the treacherous palace and trying to rewrite Jinzong's tragic fate.
When Su Wan's medicinal scheme nearly comes to light, Jinzong's secret is at risk of being exposed, and Wei Yanwan's plots keep coming one after another, can this unusual couple trapped within the Forbidden City's walls break free of the constraints of their identities and their era, and find a glimmer of hope and true love behind the red walls?
