Undercover Us Season 1, Episode 4: Episode 4

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Episode 1

Under tyrant Xie Cizhou’s brutal rule, assassin Si Yao survives a lethal trial to join Wuming Pavilion. A chance encounter with seemingly frivolous prince Xie Ciyuan sparks an alliance neither fully understands.

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Episode 2

Assassin bride Si Yao enters a marriage of deception with prince Xie Ciyuan — each plotting against the other, while tyrant Xie Cizhou watches with dangerous amusement.

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Episode 3

After a failed assassination, Si Yao and Xie Ciyuan perform a flawless cover-up. When he realizes she can calm the deadly parasite inside him, suspicion turns into something far more personal.

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Episode 4

While exposing corruption, Si Yao earns the quiet support of Xie Ciyuan. A hidden message reveals a darker conspiracy and missing women tied to powerful men.

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Episode 5

When poison leaves Si Yao near death, Xie Ciyuan drops his mask to save her. A desperate kiss binds their fates — as secrets between them deepen.

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Episode 6

As trust falters, Si Yao learns Xie Ciyuan is bound by a parasitic curse planted by his sister, Xie Cizhou — a weapon of control forged in blood.

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Episode 7

Compassion turns intimate as Si Yao soothes Xie Ciyuan’s agony. But clues hidden in her blood suggest a past tied to the mysterious Huanhua Valley.

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Episode 8

Searching for answers, Xie Ciyuan leads Si Yao toward her buried past but the name “Huanhua Valley” unlocks pain she cannot remember.

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Episode 9

Risking everything, Xie Ciyuan sneaks into the lion’s den to see his captive mother — promising freedom as rebellion begins to stir.

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Episode 10

A daring prison break exposes a larger conspiracy. Si Yao and Xie Ciyuan uncover ties between the Grand Tutor and the growing wave of disappearances.

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Episode 11

Under cover of plague, Si Yao and Xie Ciyuan infiltrate Lu City — where desperate parents reveal the terrifying scale of vanished daughters.

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Episode 12

Bloodied but unbroken, Xie Ciyuan closes in on a trafficking ring — as Si Yao uncovers a web linking officials, merchants, and hidden buyers.

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Episode 13

A shocking confession reveals Xie Cizhou uses young women’s blood for forbidden alchemy, forcing Si Yao and Xie Ciyuan toward open rebellion.

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Episode 14

When Shi An reveals Si Yao is truly Fang Muwan, lost heir of Huanhua Valley, her memory returns — along with the devastating truth that Xie Ciyuan used her heart’s blood.

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Episode 15

Heartbroken and betrayed, Fang Muwan walks away. Xie Ciyuan, freed from his curse, realizes the cost of survival may be losing her forever.

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Episode 16

Identity unmasked, Xie Ciyuan faces execution, until his mother sacrifices herself, breaking the last chain binding him to fear.

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Episode 17

Believed dead, Xie Ciyuan secretly escapes toward Huanhua Valley, while Fang Muwan collapses under the weight of grief and doubt.

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Episode 18

On the day Fang Muwan agrees to wed Shi An, a dying Xie Ciyuan crashes the ceremony — begging not for love, but for life.

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Episode 19

Forced to witness her marriage, Xie Ciyuan collapses in heartbreak, his damaged body finally surrendering to pain.

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Episode 20

Choosing love over duty, Fang Muwan stops her own wedding to save Xie Ciyuan, finally confronting feelings she can no longer deny.

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Episode 21

As jealousy simmers, Shi An challenges Xie Ciyuan’s presence. Torn between loyalty and love, Fang Muwan stands at the center of a fragile truce.

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Episode 22

Empowered by stolen blood, Xie Cizhou grows stronger, while Fang Muwan and Xie Ciyuan prepare for a final reckoning.

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Episode 23

War reaches Huanhua Valley. Amid betrayal and sacrifice, Fang Muwan falls into Xie Cizhou’s hands as allies perish.

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Episode 24

In a brutal final clash, Shi An sacrifices himself, Xie Cizhou falls, and love proves irreversible. Years later, Fang Muwan and Xie Ciyuan rule apart — bound by memory, not destiny.