Original: 鐵探
A thrilling story revolving around a policeman who becomes embroiled in a conspiracy plaguing the high-ranking officials due to an incident that almost cost him his life.
Sheung Sing leads the team and charges into the drug den, but they are stopped by the Narcotics Bureau. Sheung Ching and Wing Jing are held hostage.
Matt prepares to make an arrest with his team and refuses to let Sheung Sing take part. The identity of an officer undercover is about to be exposed.
Sheung Sing and Matt subdue the drug dealer and obtain new clues. Hiu Yee is disheartened when Sheung Sing focuses solely on investigating the case.
Sheung Sing and his men are assigned to destroy the drugs, but are forced to divert their route. Hiu Yee and Sheung Ching move in with Sheung Sing.
The escort vehicle is ambushed by the Beast, and someone falls in the midst of gunfight. Hei Wah explains the case to the media.
Walking a thin line between both sides, Bingo can no longer define his identity. A newly awakened Sheung Sing is embroiled in a power struggle.
Hei Yi drags Matt to celebrate her discharge from the hospital. After Wing Jing confides a secret to Sheung Sing, their bond becomes stronger.
In spite of the aftereffects, Sheung Sing insists on going back to the frontline. Wing Jing disappears after having a heated argument with Hei Wah.
Sheung Sing looks forward to returning to the RCU soon, but Hei Wah looks down upon his request. Hei Wah turns to Mr. Kan for help.
Hei Wah conceals the truth behind the case in hope to provoke the real culprit to show up, but Sheung Sing openly contradicts her.
Sheung Sing is expelled from the team and undergoes internal investigation. Hei Wah, who excels in her job, takes over the kidnap investigation.
Sheung Sing and Hei Yi investigate the kidnap by following the clues. The case has a breakthrough after they apprehend Ah Lei.
Bingo suddenly withdraws his confession and asks to speak to Sheung Sing alone. Sheung Sing promises to release Bingo under certain conditions.
Sheung Sing is hospitalized again. Luckily, he receives a good news. Samuel points out the actual cause of the bottleneck Hei Yi encounters at work.
Hei Wah invites Matt to transfer to the RCU, but he turns her down. Finding himself in an unfavorable position, Samuel finds a chance to fight back.
Samuel and Carrie join forces to shake up the status of Hei Wah. Hei Wah uses the death of Chun to get through a crisis for the time being.
Hei Wah heeds Mr. Kan's warning and joins forces with him to counter Samuel. Sheung Sing is discharged. A wrist watch triggers Wing Jing's memory.
Worried about Tung Tung's safety, Bingo asks someone to look after her. Samuel asks Matt to convince Sheung Sing to stay in the RCU.
Sheung Sing receives the first mission after his return. Hei Wah asks Wing Jing to persuade Iris to gather evidence, who agrees for old time's sake.
Sheung Sing and others pull themselves together to gather evidence against Ching Lung. Sheung Ching runs into Tung Tung, and the two fall into danger.
The investigation stalls. Sheung Sing's suggestion causes a fierce dispute between him and Wing Jing. Bingo finds himself in an unfavorable position.
Matt takes the blame for Sheung Sing. Hei Wah leaves the matter to Samuel to deal with. Samuel begins to investigate on the mole.
Iris assists the police in finding the criminal and the cache of drugs. Hei Wah rains against Matt, but she later learns of a harsh truth from him.
Wing Sa reveals her identity to Bingo, and the two discover something together. There is a glimmer of hope for Hiu Yee and Sheung Sing's relationship.
Hei Wah starts off with the wrong foot as she leads the team during an operation. The rape and murder case evokes the painful memories for Hei Yi.
Hei Wah wants Hei Yi to be the bait, but Sheung Sing strongly opposes. The arrest operation begins, yet the killer changes his target unexpectedly.
The police narrows down the rape suspect. Someone secretly reports the RCU's operations to the Commander. Bingo reveals Hei Wah's secret.
Vowing to take down Hei Wah, Sheung Sing joins forces with Samuel and Mr. Kan in search of evidence. Sheung Sing's sequelae are getting worse.
Sheung Sing plans to sue Hei Wah, but the chances of winning the case are slim. On the day of the court session, Wing Jing seems to have changed.
The trial resumes. Hei Wah gains the upper hand by exploiting the death of her sons. Hei Wah goes to see the Commander and learns an inevitable truth.
