Princess Royal Li Rong and Prime Minister Pei Wen Xuan are husband and wife, but they're not in a harmonious state. They also have different political views. Emperor Li Chuan of the Great Xia is in danger of death due to elixir poisoning, and it's urgent to appoint a crown prince. Li Rong advocates that the son of Empress Shangguan Ya be the crown prince, while Pei Wen Xuan insists on supporting the son of Concubine Qin Zhen Zhen to inherit the throne. The two, who have been living separately, will be at loggerheads again because of this matter when they meet.

Su Rong Qing is happy when Li Rong invites him to a meal. He goes to the restaurant, but Li Rong doesn't appear. He is sad. Su Rong Hua knows Su Rong Qing is sad, so they get drunk together. Back at home, Li Rong helps Pei Wen Xuan dress his wounds. Both of them have a heart-to-heart talk. Pei Wen Xuan feels very touched and sleeps with Li Rong in his arms.

Li Chuan musters enough courage and heads to Jiulu Mountain to confess to Qin Zhen Zhen. The Qixi Festival Banquet begins. Pei Wen Xuan receives news that Consort Rou held an incense-making contest for the ladies to help her niece, Xiao Wei, enter the Eastern Palace.

When the crown prince attacks the capital with Xun Chuan's troops, Consort Rou enters the palace and abducts Li Ming. She was shot to death with an arrow. Su Rong Qing realizes he is at a disadvantage and goes to find the emperor's dying edict. Pei Wen Xuan pursues him and they fight each other.

Returning to her 18-year-old self, Li Rong intends to use the Spring Banquet to choose a prince consort again. Despite her previous entanglements with Pei Wen Xuan, she now sees him as nothing more than an inexperienced young man under 20. Thus, she plans to tease him a little for her amusement.

Li Rong and Pei Wen Xuan test each other and arrive at the same conclusion, the other person has also come back in time. Both of them stop hiding their pasts and think there is no need to repeat their past mistakes. Pei Wen Xuan no longer suggests being the prince consort and even explains the best prince consort candidate to Li Rong.

Li Rong heads to the grand hall alone to confront the soldiers of the noble families. Su Rong Qing and the soldiers of the Su family arrive at the grand hall. They thought that Li Chuan would be in the hall, but instead, it was Li Rong.

The next morning, Li Chuan and Su Rong Qing, who serves as the Vice Minister of Justice, lead a group of men to find Li Rong and Pei Wen Xuan. Just having learned that the one who killed her was Su Rong Qing, Li Rong feels a mix of guilt and conflicted emotions upon seeing him again.

Upon learning of the prince consort's assassination, Li Rong is consumed by fury. She vows to bring the perpetrators to justice. Disguising her true intentions as a simple outing, Li Rong decides to use herself as bait to lure the assassins out of hiding.

Pei Wen Xuan asks Li Rong out on a date during her off day. But Li Rong has promised Cui Yu Lang that they'll discuss the imperial examination case on her off day. So, she rejects Pei Wen Xuan. Pei Wen Xuan becomes suspicious and decides to follow Li Rong.

Li Rong plays along and reveals to Consort Rou her intention to hand over control of the Inspectorate. Meanwhile, Consort Rou hints that since Li Rong and Pei Wen xuan are divorced, it would be best for them to meet less frequently. It seems Consort Rou has discovered their secret meetings, making Li Rong feel threatened.

Li Rong and Pei Wen Xuan argue frequently, their bickering a daily occurrence, yet they exhibit perfect harmony when it comes to strategy. While investigating the Yang family, they simultaneously begin amassing military strength for the crown prince. In a display of tacit understanding, they temporarily set aside their past grievances involving Qin Zhen Zhen and travel together to Jiulu Mountain, seeking to enlist the help of Qin Zhen Zhen’s brother, the brave General Qin Lin, who has been living in seclusion in the mountains.

Upon returning to Pei's Residence, Pei Wen Xuan and Li Rong engage in a fierce argument to reclaim the inheritance left by Pei Wen Xuan's father, only to be met with adamant refusal from Pei Li Xian and their other relatives. At a crucial moment, the timid Madam Wen, inspired by Li Rong's unwavering support, finds her voice and boldly denounces the Pei family members for their ungratefulness.

Pei Wen Xuan decides to pretend to divorce Li Rong and uses the opportunity to point out that the marriage talisman was forged by Consort Rou, in order to alleviate Li Ming's suspicions.

Pei Wen Xuan has just left Qionghua Palace when he is summoned to the Imperial Study by Li Ming. Yang Quan is already waiting there, his eyes burning with envy at the sight of Pei Wen Xuan. Despite Pei Wen Xuan's sarcastic remarks, Yang Quan has no choice but to implore Li Ming to grant his marriage to Li Rong. However, Li Ming remains indifferent.

Pei Wen Xuan expresses that Li Rong was the only person he loved in the past. He never had any feelings for Qin Zhen Zhen. Li Rong becomes speechless, and she chooses to avoid him. Her cold attitude chills Pei Wen Xuan's heart.

Li Rong orders Xun Chuan to find the veterans and obtain their testimonies. At the same time, she intends to acquire information from the Ministry of Justice. Pei Wen Xuan was bullied in the Censorate as he went against the noble families. He has to work overtime day after day.

At the execution site, the noble families keep applying pressure on Li Ming. Just when Li Ming is about to execute them, Pei Wen Xuan finally returns with the evidence.

Li Rong solves the case and becomes the Head Inspector of the Inspectorate. The Inspectorate is established officially. At the same time, Li Ming assigned Su Rong Hua as the Vice Inspector to control Li Rong.

The next morning at the imperial court, Xie Lan Qing brings Lin Fei Bai to accuse Li Rong of an assassination attempt according to Su Rong Qing's instructions but it backfires when Li Rong counters his accusation.

Li Rong and Pei Wen Xuan make decisive choices, using their past investigations to come up with countermeasures. But they feel that Consort Rou alone cannot come up with such plots. However, she's familiar with the delay of Crown Prince's wedding. They realize that Su Rong Qing taught Li Rong that idea in their past life. Only then did they realize that Su Rong Qing was...

Feeling desolate after losing Consort Rou, Li Ming summons Xiao Qian to the palace. Upon hearing this, Li Rong deduces that Li Ming intends to recall the troops to the capital.

Li Cheng dies from poisoning. Xiao Qian brings in Li Cheng's double and burns his corpse.

Li Rong sees Li Chuan again. They reminisce about the past together. Li Chuan says that his wish is to embark on a northern expedition as his mother said that the northern part was plagued by war. If they lose the war, Li Rong, his eldest sister, will be sent there to establish a marriage alliance.

With the regime undergoing a major shift, the fate of Pei Wen Xuan's family hinges on who holds the family master's token and the key to the treasury.