Key Witness

Interpol officer Xu Guo Ying resigns. Kwon Seung-hyun accused of murder, seeks Hannah with Korean police.

Hannah escapes kidnappers, accuses Kwon Seung-hyun of murder but is coerced. Guo Ying learns of her sister held hostage.

Guo Ying rescues Hannah's sister and she exposes Gong Jung-hoon as the real killer.

Investigating, Ying Jie finds Yu Wen Guang's passport, presumed dead. Guo Ying, Yu Xuan, and Zhi Ming discover his bones

Guo Ying requests drug files from Ying Jie, who refuses. She confronts Yao Kang, who gives her fake documents

Yu Xuan guides Guo Ying to meet Li Na, trailing her covertly. Li Na notices. Guo Ying confronts her about Wen Guang.

Guo Ying confronts Li Na on a yacht about Wen Guang. Li Na poisons her and flees. Zhi Ming aids Guo Ying ashore.

Guo Ying got a tip on arms smuggling evidence. Ying Jie investigates. Guo Ying realizing her father Yao Kang is the mole

After failing to protect a witness, Guo Ying resigned from Interpol. She began hunting witnesses with her friends

Mary invites Guo Ying and Yu Xuan to dinner. Yu Xuan learns Zhi Ming was adopted, sparking memories of his kidnapping.

Guo Ying questions Dex about a tattoo and gets a Thai tattoo master's card. Yu Xuan learns Dex's dark past from Johnny

Guo Ying reveals victims were Myanmar rebels from a massacre. Yu Xuan warns Dex, who avoids discussion.

Dex and Da Peng interrogate Dan Nong in a freezer warehouse. Guo Ying arrives with her team. Da Peng kills Dan Nong

Hong Kong police request Nick to testify, but he's kidnapped, tied up, and thrown into the sea. Guo Ying rescues him.

Li Na dangles info on Guo Ying's mother's death. Yao Kang orders a search, wary of Guo Ying's pursuit of truth of her mom

Guo Ying discovers Yao Kang's ring at Li Na's, linking him to her mother's death. She uncovers his betrayal.

Guo Ying accidentally kills Antonio in a car accident, seeks Yao Kang's help to cover it up. Ying Jie suspects her.

Mary hires an assassin to eliminate Dex and Yu Xuan. They fall into a trap and Dex sacrifices himself for Yu Xuan

In a moment of critical decision, Zhi Ming chooses to disarm the bomb on Mary to save Guo Ying and Yu Xuan.