David receives a phone call that will change his life – a mysterious, distorted voice who identifies himself as Zero orders him to do his bidding, otherwise someone he loves will die. David hangs up the phone on Zero. Hours later, his wife, Julie lies in hospital, the victim of a hit and run. Zero and David form an uneasy alliance; with David reluctantly agreeing to do Zero’s bidding. His first assignment – to hunt down and catch the Bukit Aman Rapist, a sex predator who has been terrifying the neighbourhood.

As the Bukit Aman Rapist can now identify David, Zero forces David to hunt him down and kill him. In addition, David must also contend with a pair of International Robbers who have brutally beaten and robbed Julie’s mother. Meanwhile, Maddy is beginning to suspect that David is having an affair.

Winnie re-enters David’s life with an ultimatum of her own – she wants David to finish what he started years ago and take down Roy, her ex-boyfriend who raped and brutally beat her. She reveals that she knows David’s secret – that he is the so-called vigilante who killed the Bukit Aman Rapist and the International Robbers. David wonders if Winnie is behind the whole Zero affair.

Things come to a head at home when Julie confronts David about his supposed affair with Winnie. Meanwhile, David receives his toughest assignment from Zero yet – going after a corrupt police officer, Inspector Leong. Ironically, Inspector Leong is the in charge of his case, so hunter becomes the hunted and vice versa.

David personal and professional life fall apart as a result of the Zero affair – in addition to tensions at home, he is asked to leave his job when evidence surfaces that he might have fixed the company accounts. In the meantime, Zero is putting pressure on him to confront Inspector Leong and bring him to justice. The more David rejects Winnie, the more she comes after him. When Julie can no longer bear it, she sets out to confront Winnie in a showdown.

Inspector Leong lays a trap for David, forcing him to run. David is now a fugitive from the law and not even Zero can help him. Julie is held hostage by Winnie, who drugs her in order to keep her under control. And Maddy unwitting falls into a trap Zero has laid for her, in order to force David to do his final bidding.

Zero and David finally confront each other face-to-face in a showdown that could take the life of Maddy. The police also tighten their net around David and try to arrest him and bring him in. In the aftermath of this showdown, who will win and who will live?

David tries to pick up the pieces of his life after his encounter with the Zero Legion only to be drawn into the hunt again by two mysterious law enforcers, Agent Fong and Agent Dhillon. Meanwhile, a new vigilante is on the loose, killing gangsters and child molesters, among others.

Maddy is being bullied in school. Beverly, her lecturer who is also a mentor for the Zero Legion, wins her trust by helping her exact vengeance on her aggressors. David’s relationship with Maddy goes downhill when he tries to get involved.

David helps the Task Force hunt down the vigilante who, like him before, has been forced by a Zero to execute Targets. When David finds out the vigilante, Sam, is a 19-year-old girl, he is conflicted about giving her up. He tries to stop Agent Fong but in the process, puts his own life at risk.

Beverly tries to convert Maddy over to the Zero Legion. Meanwhile, the Task Force closes in around Beverly, causing her to kidnap Maddy. David tries to intervene, only to find himself in a deadly life-and-death situation. Meanwhile, Sam seeks refuge at David’s flat.

There is a crisis at the Task Force Control Centre: the Zero Legion has hacked into their systems, thanks to a mole among the team. David, Agent Fong, Agent Dhillon and Ben are caught in the middle of a tense, action-packed showdown between good agents and their betrayers.

Zero One makes Maddy prove her allegiance to the Zero Legion by killing her first Target – Agent Dhillon. David is shocked when he finds out his own stepdaughter has joined the Zero Legion; he tries to find Maddy before she commits the deed.

Agent Fong gives David an ultimatum – hand over Sam or they will hunt down Maddy. David is forced to obey, but he is unaware that the Task Force already has plans of their own for Maddy.

Maddy heads to a remote island to rendezvous with Zero One as David and the Task Force try to trace her whereabouts. Julie returns to Singapore after a long soul-searching journey abroad and berates David for what he has done to Maddy. Sam, who is still on the loose, takes refuge with a trusted acquaintance from the past.

Agent Fong and David are taken hostage on the remote island by the Zero Legion and forced to undergo torture. Maddy – who is on the same island and now part of the Legion – is given the ultimate test: kill David.

When Maddy refuses to kill David, they are taken out into the forest to be killed. David manages to fight his way out – but now, they must return to the Zero Legion’s safe house to rescue Agent Fong. Meanwhile, Julie finds out the truth about the Task Force.

The Task Force Command Centre receives a surprise visitor – Sam, come to give herself up. Agent Dhillon races to locate David and Agent Fong, unaware of a surprise attack that is about befall the Command Centre. Meanwhile, David and Agent Fong try to find their way back to Singapore.

Sam takes Agent Dhillon hostage in the Task Force Command Centre. David and Maddy return to Singapore only to find out that Julie has been kidnapped by someone from the Zero Legion. The clock ticks as David races to save Julie while Agent Dhillon tries to prevent his own execution.

David, Julie and Maddy are now reunited, but for them, danger lurks just around the corner. Agent Dhillon and Agent Fong face the disbandment of the Task Force, just as new threats emerge.