Mai Tian prays for her missing elder brother by a streamer. She passes by Ye Wuming, the crown prince, who falls off a cliff later. She carries the unconscious prince home to her adoptive father Mai Tianlin, who suspects the stranger’s extraordinary identity. When Ye Wuming regains consciousness, he hides in Mai Tian’s bathing tub and grabs her neck in panic. Their struggle injures his head again, erasing all his memories. Assassin Shen Zhifeng tracks the prince to Penglai Village via blood trails. Meanwhile, the county magistrate covets Mai Tian and arrests her, forcing her to become his concubine. Just as she stumbles for an excuse about a fiancé, Mai Tianlin arrives with the amnesiac Ye Wuming.

With no recollection of his past, the prince is named Ye Wuming by the Mai family. To fend off the magistrate, Mai Tian lies that they privately engaged each other. To save her reputation, Ye Wuming signs a marriage certificate in public. The magistrate threatens the whole family with treason if they refuse to wed. Later, Ye Wuming worries he will ruin Mai Tian’s life with a fake marriage. Heartbroken, Mai Tian plans to submit to the magistrate, but Ye Wuming chases her in rain and agrees to marry her. A grand wedding banquet is held, yet Shen Zhifeng sneaks in. He uses incense to knock the newlyweds unconscious, ready to kill the prince at the nuptial chamber.

Shen Zhifeng halts his assassination after spotting Mai Tian’s jade pendant, which belongs to his lost sister Shen Zhinian. Crown Princess Qiu Yi summons him and demands the prince’s corpse, while Prime Minister Qiu approves of her plot to murder the heir. The next day, Mai Tian and Ye Wuming visit a temple to pray. Having no concept of money, Ye Wuming borrows one hundred taels of usury to buy fine furniture and silk for Mai Tian. Enraged by the huge debt, Mai Tian wants to divorce him. Ye Wuming vows to open an errand shop to pay it off. Shen Zhifeng scolds the loan shark Ding Wu for lending money to the prince.

Ye Wuming’s errand shop gains no profitable orders. The couple takes a copywriting job at a bookstore for extra cash. Reading a romantic novel aloud at night fills the room with ambiguous tension. Mai Tian sprains her ankle delivering herbs to an old mountain woman, and Ye Wuming rushes to carry her back amid falling rocks. At home, Mai Tianlin finds a jade pendant in Ye Wuming’s clothes and suspects he is Mai Tian’s blood brother. While picking wild vegetables in a valley, Ye Wuming accidentally eats epimedium and suffers extreme body heat.

Mai Tian wakes up nestled in Ye Wuming’s arms after their intimate night, both embarrassed and flustered. Mai Tianlin shows the jade pendant to Mai Tian, claiming Ye Wuming is her long-lost brother and vowing to separate them. That night, Ye Wuming confesses sincerely, and they become genuine spouses. The next day, Mai Tian runs into Shen Zhifeng in town. Ye Wuming sees them talking and flies into a jealous rage. Ding Wu and his gang suddenly appear to demand debt repayment. When Ye Wuming cannot pay, the thugs threaten to sell Mai Tian to a tavern, sparking a fight.

Ding Wu draws a dagger and stabs toward Ye Wuming. Mai Tian blocks the blade and collapses bleeding. Shen Zhifeng kicks the thug away and pays him to leave. Back home, Mai Tianlin reveals the jade pendant story, making Mai Tian doubt Ye Wuming is her brother. When she questions him, Ye Wuming recalls the street scene and accuses her of infidelity. Their misunderstanding deepens. Later, Shen Zhifeng kills Ding Wu for hurting his sister, then disguises the thug’s body as the prince’s to deceive Prime Minister Qiu.

Ye Wuming asks Mai Xiang whether Mai Tian had male suitors before their marriage. Dejected, Mai Tian drinks alone at an inn, where Shen Zhifeng finds her and listens to her troubles. Ye Wuming spots them drinking together, gets drunk and confronts the two. To distance herself from Ye Wuming—whom she still believes is her brother—Mai Tian lies that Shen Zhifeng is her lover. Infuriated, Ye Wuming proposes a divorce, and Mai Tian agrees. Shen Zhifeng stays silent, hoping his sister can break ties with the prince.

Mai Tian holds an umbrella over heartbroken Ye Wuming in heavy rain but returns to Shen Zhifeng right after, worsening Ye Wuming’s despair. At Guanyin Temple, Mai Tian notices a ribbon tied in her brother’s unique style, which Ye Wuming cannot replicate, making her suspect he is not her blood kin. Distraught, she accidentally tears their marriage certificate and conceals it in Ye Wuming’s quarters. The next morning, Mai Xiang finds the torn paper and thinks Ye Wuming wants a separation. Ye Wuming sees the jade pendant and grows suspicious of all the odd incidents. Meanwhile, scholar Liu Chen falsely accuses Mai Tian of selling fake medicine, and the biased magistrate orders her to pay a five-hundred-tael fine.