If you haven't watched Princess Agent yet and want to watch this series straight away, here's a summary of the story, sorry, this is full of spoilers for Princess Agent:

1. Chapter One: Training and Identity (Eps 1 - 20)
Introduction: Chu Qiao (living as a slave named Jing Xiao Liu) is the sole survivor of a "human hunting" game played by cruel aristocrats. She is indirectly saved by Yan Xun and brought into the household of Yuwen Yue(zhuge Yue).

Spy Training: Yuwen Yue (Zhuge Yue )recognizes Chu Qiao’s extraordinary combat talent. He trains her brutally to become an elite spy (Bedwarmer Spy). During this time, Yuwen Yue(Zhuge Yue) begins to fall in love with her, but he maintains a cold exterior to toughen her mental resolve.

Death of Siblings: Chu Qiao’s adoptive siblings (fellow slaves) are slaughtered by the evil Yuwen family, specifically by Yuwen Huai. This plants the seeds of hatred in Chu Qiao toward the Yuwen clan, including Yuwen Yue.

Minor Villains’ Demise: Chu Qiao’s adoptive brother, Lin Xi, dies due to a trap. Chu Qiao begins her revenge, systematically eliminating the cruel senior servants.

2. Chapter Two: The Tragedy of the Yan Family (Eps 21 - 30)
The Conspiracy: The paranoid Emperor orders the massacre of the Yan family in Yanbei. Yan Xun, who is celebrating his birthday in the capital, suddenly becomes a wanted fugitive.

Jiuyou Platform (Iconic Moment): Yan Xun is brought to the execution stage. Before his eyes, he sees the severed heads of his father and brothers. He rages in agony but is brutally beaten down.

A Mother’s Sacrifice: Yan Xun’s mother, Bai Sheng, appears and sacrifices her own life in front of the Emperor to beg for mercy for Yan Xun, the last survivor of their bloodline.

3-Year Imprisonment: Yan Xun and Chu Qiao are confined in the Ying Ge Pavilion. Chu Qiao becomes a total protector for the mentally shattered Yan Xun. They rely on each other to survive nightly assassination attempts orchestrated by Yuwen Huai.

3. Chapter Three: Awakening & Revenge (Eps 31 - 45)
The Escape: Their imprisonment ends. Yan Xun pretends to submit and agrees to marry Princess Yuan Chun as a tactic to escape back to Yanbei.

Bloody Rebellion: On the wedding day, Yan Xun launches a massive rebellion in the capital. He abandons Yuan Chun at the altar and slaughters the imperial forces.

Yuan Chun’s Tragedy: The pitiful Princess Yuan Chun tries to chase Yan Xun to the border, but she is instead raped by Yanbei soldiers who hold a grudge against the Empire. This transforms her into a villain consumed by hatred for Chu Qiao (whom she blames for stealing Yan Xun).

Yan Xun’s Transformation: Yan Xun arrives in Yanbei, but he is no longer the cheerful man he once was. He becomes a cold, bloodthirsty military leader.

4. Chapter Four: Ideological Conflict (Eps 46 - 55)
Chu Qiao vs. Yan Xun: Chu Qiao wants to abolish slavery and bring peace, but Yan Xun only seeks the total destruction of the Wei Empire. Yan Xun begins massacring his own disloyal subordinates and using "dirty" tactics that disgust Chu Qiao.

The Return of Yuwen Yue (Zhuge Yue ): Yuwen Yue(Zhuge Yue ) reappears as a General. He repeatedly saves Chu Qiao from deadly situations in secret. Chu Qiao begins to realize that Yuwen Yue has been the most sincere person in her life all along, not Yan Xun.

Villains’ Demise:

Yuwen Huai: Dies a gruesome death, beheaded by Chu Qiao during an invasion.

Wei Shuye: Dies while trying to protect Princess Yuan Chun.

5. Final Chapter: The Frozen Lake (Eps 56 - 58)
The Deadly Trap: Jealous of the bond between Chu Qiao and Yuwen Yue, Yan Xun uses Chu Qiao as bait (sending a fake letter) to lure Yuwen Yue alone to a frozen lake.

Battle on the Ice: Knowing it is a trap, Yuwen Yue goes anyway for Chu Qiao’s safety. He is surrounded by thousands of Yan Xun’s soldiers and shot multiple times with arrows.

The Dramatic Moment: Chu Qiao arrives and finds Yuwen Yue dying. She cries and kisses his forehead, finally admitting her love. However, the ice breaks and Yuwen Yue ( Zhuge Yue ) sinks into the water.

The Ending: Chu Qiao jumps into the freezing water to save him. Under the water, Yuwen Yue pushes Chu Qiao back to the surface so she can live. Due to the extreme cold and intense emotions, the Spider Lily mark on Chu Qiao’s shoulder glows brightly—her "Ice Formula" internal power fully awakens.

SUMMARY OF CENTRAL CHARACTER DEATHS:
The Yan Family (Father & Brothers): Beheaded due to framed treason.

Bai Sheng (Yan Xun’s Mother): Commits suicide to save Yan Xun.

Yuwen Huai (Main Villain): Beheaded by Chu Qiao.

1. Chu Qiao
Initial Identity: Known as Jing Xiao Liu, a slave with amnesia.

True Identity: Daughter of Luo He, the leader of "Jianghu Die Zhe" (People's Alliance), a secret intelligence network.

Inner Power: Possesses the Han Bing Jue (Ice Formula). It was sealed for most of the story and only fully awakened in the final scene at the frozen lake.

The Conflict: She is torn between her gratitude/loyalty to Yan Xun and her growing love for Yuwen Yue, who shares her ideals of justice and ending slavery.

2. Yuwen Yue / Zhuge Yue (The Protector)
Role: The stoic leader of "Eyes of God" (Imperial Spy Network).

Relationship: He trains Chu Qiao as a spy to help her survive. Despite his cold exterior, he repeatedly risks his life and reputation to save her from the shadows.

Final Fate: He is lured into a trap by Yan Xun. He is shot and falls into a frozen lake, choosing to drown to push Chu Qiao to safety.

3. Yan Xun (The Fallen Hero)
Role: Prince of Yanbei. Initially bright and kind.

Relationship: He and Chu Qiao support each other through 3 years of imprisonment.

The Turn: After the brutal execution of his entire family, he becomes a ruthless, vengeful tyrant. He eventually uses Chu Qiao as bait to kill Yuwen Yue, leading to his permanent fallout with her.