Because of political reasons, princess Li Rong and Pei Wenxuan got married at the age of 18. In the end they drifted further and further afar from each other. After 20 years of a loveless marriage, they were manipulated into turning against each other, leading to their deaths. However, they wake up back at 18, before their marriage, facing the hardest time of their lives. The two of them are given second change together, to save those around them.
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.
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.
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.
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 takes advantage of the situation to file a report on Yang Quan to Li Ming. After Yang Quan fails to kidnap the princess, he assassinates a court official. Moreover, he continues to get defeated on the northwest battlefield. Wen Xuan voices out that there's something fishy going on. Li Ming takes that opportunity to promote Pei Wen Xuan to a censor and asks him to investigate the Yang family.
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.
After Li Rong is imprisoned, Liu Chuan visits her in prison. A lady was following him. It turns out that the lady is Qin Zhen Zhen. Pei Wen Xuan thought that Qin Zhen Zhen canceled the marriage because her family forced her to do so. However, Qin Zhen Zhen says that she did so of her own accord.
To promote Prince Su, Li Ming decides to send Consort Rou's brother, Xiao Su, to the frontline to replace Li Chuan. A day before the wedding, Pei Wen Xuan hands out red envelopes to other officials. And Su Rong Qing shows up unexpectedly.
On their wedding night, Li Rong and Pei Wen Xuan can't sleep well. Instead, they discuss plans for after their divorce. Pei Wen Xuan deliberately arranges for Su Rong Qing to pick her up during their wedding day, while Li Rong is also thinking about how to stop Qin Zhen Zhen from entering the palace.
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.
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.
Pei Wen Xuan suggests to Li Rong that she establish the Inspectorate, leaving Li Rong in a dilemma. Qin Zhen Zhen is grateful to Li Rong for saving her life, while Li Rong plans for Qin Zhen Zhen to live on under the identity of a guard, Xun Chuan.
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.
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.
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.
With no other options, Li Rong secretly sends Pei Wen Xuan out of the capital to gather evidence. He has to return before the scheduled execution of the Qin family. Li Rong, under immense pressure, rescues the Qin family from the Ministry of Justice and shelters them in her residence, while Su Rong Qing arrives to intervene.
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.
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.
Li Rong uncovers the identity of the assassin leader and learns about the mastermind behind. Li Rong proposes a deal with Lin Fei Bai to assassinate Xie Lan Qing instead. Lin Fei Bai finds himself in a dilemma.
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.
Lin Fei Bai was sentenced to military exile to the southwest border. Before his departure, Shangguan Ya goes to see him off. The intensity of their conflict was greatly reduced. Before Lin Fei Bai's departure, Shangguan Ya gives him a set of Leaf Cards, forming an affinity between them.
With the supplementary examination approaching, Pei Wen Xuan is determined not to be outdone and is pulling out all the stops to attract scholars, engaging in a competition with Su Rong Qing. Unexpectedly, Su Rong Qing’s enthusiastic efforts to host scholars from all over the country seem to have an ulterior motive.
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...
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.
Li Rong and Su Rong Qing confront each other in front of Li Ming at the imperial study. With Hong De's suicide and his son's disappearance, Li Ming suspects Su Rong Qing. Li Ming questions Su Rong Qing if he is the culprit.
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.
Consort Rou is in charge of investigating the examination fraud case. She's in trouble as the noble families make things difficult for her. Li Ming suggests her to use Pei Wen Xuan. Pei Wen Xuan acts as if he's loyal to the emperor. Consort Rou is happy with his performance. She has no idea that Pei Wen Xuan has ulterior motives.
Li Rong waits patiently for the conflict between Consort Rou and the noble families to reach its climax. After that, she arranges for Chen Hou Zhao to return to the capital. She prepares evidence and threats of Consort Rou's threats to dissuade students from filing complaints, launching a vigorous counterattack in court and defeating Consort Rou in one fell swoop.
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 Ming proposes to hold a Winter Celebration, hoping to make a final stand at the banquet. During the banquet, everyone has their own schemes. Lin Fei Bai and Su Rong Hua compete in a lion dance fight as a performance. But they are actually fighting against each other as love rivals over Shangguan Ya. The fight is fierce and intense. In the end, both are injured.
In the past, Su Rong Qing did not kill Li Rong. He gave Pei Wen Xuan a fragrance pouch to slow down the poison of Fragrant Beauty. It means Li Rong was already poisoned before she fell ill. Li Rong never expects that instead of her husband, who has opposed her for decades, and Su Rong Qing, who has a deep grudge against her, it is her brother, Li Chuan, who wants to harm her.
Li Cheng dies from poisoning. Xiao Qian brings in Li Cheng's double and burns his corpse.
Pei Wen Xuan knows Li Rong's issue has been resolved and guides her patiently. He tells her the truth about the past and hopes Li Rong can untie the knot in her heart.
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.
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.
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.
