Trinity of Shadows

Detective Tze Wei is handling an assault case. When the police arrive at the scene, the victim Nicole decides not to press charges against the perpetrator, stunning Tze Wei.

Ordered to do administrative work, Tze-Wei receives an unexpected call for backup from a rookie police officer, Chia-Hao, who is investigating the case of absconded migrant workers. Disregarding protocol, Tze-Wei rushes to Chia-Hao’s aid.

City Councilor Yang Chi Hsiao is shot in his electoral district. Tze Wei rushes to the scene immediately and makes an unexpected discovery.

Tze-Wei takes on the task to safeguard Chi-Hsiao and identifies the shooter as a wanted criminal. Meanwhile, Nicole’s neighbour, Ching-Yao, discovers a body while hosting his friends.

The body is identified as Jia-Jia, a young woman linked to Chi-Hsiao. While Tze-Wei and Chia-Hao suspect a police cover-up, Chi-Hsiao is already one step ahead of them.

Tze-Wei and Chia-Hao decide to work with Chi-Hsiao to investigate Ming-Chieh. When he is released due to a lack of evidence, Chia-Hao is infuriated, as his grudge is driven by personal reasons.

Tze-Wei and Chi-Hsiao continue to investigate Jia-Jia's murder. They receive a critical tip by chance. Meanwhile, Chia-Hao continues to look into Ming-Chieh on his own.

Tze-Wei believes that Chia-Hao’s disappearance is connected to Ming-Chieh’s kidnapping. Acting ahead of the other police officers, Tze-Wei tries to get ahold of Chia-Hao but to no avail.

Chia-Hao forces Ming-Chieh to confess his involvement in the murder three years ago while Tze-Wei and Chi-Hsiao attempt to talk Chia-Hao into letting Ming-Chieh go.

Investigation into Jia-Jia's murder is still ongoing but no one knows that Ta-Dong holds the answer. Meanwhile, Ta-Dong’s plan to target Tze-Wei appears to have something to do with Chi-Hsiao.

Hu Ta-Dong kidnaps Tze-Wei but refuses to reveal his motive. Tze-Wei eventually escapes, but her escape turns her into a murder suspect: She is accused by Ching-Yao of killing his classmate. In the middle of his tense election campaign, Chi-Hsiao insists on helping Tze-Wei. Unbeknownst to him, they have a connection in the past that cannot be untangled.

Chi-Hsiao continues to quietly help Tze-Wei. He also wants to figure out why Ching-Yao would frame Tze-Wei. Although he's unable to convince Ching-Yao to tell the truth, the misunderstanding between him and Tze-Wei is finally resolved. The two discover that Ching-Yao is threatened by Ta-Dong. It seems that everything is being controlled by Ta-Dong...

An unexpected death causes Tze-Wei to be even more determined to arrest the suspect. Meanwhile, Chi-Hsiao's father is displeased with his relationship with Tze-Wei and decides to take action.

Tze-Wei finally finds out who Chi-Hsiao's biological mother is while Chi-Hsiao locates Tze-Wei’s missing mother. They confront their demons and resign to the tragedy caused by their parents.

When Tze-Wei visits her grandfather at the nursing home, she runs into Ta-Dong. In that moment, Chi-Hsiao also shows up with Tze-Wei's mother. The time has come for Ta-Dong to seek revenge.