Heading up a Royal Commission into gun crime, Janet King believes solving the murder of Todd Wilson will uncover what's fuelling the violence.

After the drive-by shooting at the Nobakht's, the Royal Commission focuses on the origin of George Healy's gun and the 322,000 Todd left behind - leading to a dead body and a link to a murder.

After discovering the gun used in the drive-by was used in Ash's killing and the kneecapping of gambling addict Felix Murphy, the Commission launches an undercover operation to find out who shot Felix.

The suspicion on Karen is quickly transferred to Major Simon Hamilton and continues to mount due to his missing Ferrari, abusive reputation, no alibi for the night of Todd's murder and a shipping container full of handguns.

With increasing political pressure for the Royal Commission to deliver results, and the container full of handguns so far yielding nothing, Janet is forced to fast-track the undercover mission.

Following Brett Bonar's death, the Commission discovers he was not only the shooter at the Nobakht house and involved George Healy's killing, but he also knew Ash's killer. So who is he working for?

Despite solving Todd Wilson's murder, the political pressure on Janet culminates in a dilemma: she must either step down or suspend the Royal Commission.

With her Royal Commission suspended, Janet has to fight off the State Corruption watchdog, her political enemies, and ultimately, Ash's killer.

Senior Prosecutor Janet King returns from maternity leave to confront a high-profile murder, and a conspiracy which will have shocking ramifications throughout the judicial system.

Janet is overwhelmed with guilt about Blakely's death, and Det. Campbell believes his demise could have something to do with an old case; Erin and Owen are preoccupied with a bikie murder.

In the wake of the drive-by shooting of murder witness Zebina Petrakis, Erin finds herself emerging as a key witness herself in the case against the two bikies who committed the murder.

The search for the third man who assisted in the Blakely murder uncovers an unlikely ally for Janet and the scent of high level corruption.

Janet faces humiliation when Dianne Vasilich appeals against her conviction for murder. Her pursuit of corruption uncovers a shocking secret and sees Janet facing her greatest threat.

After the attempted murder of her family, Janet suspects that she has stumbled onto a wide-ranging conspiracy involving powerful and well-connected paedophiles, including Judge Renmark.

A sudden death, a false suspect and a shocking revelation from the witness box all conspire to block Janet's desperate search for the truth.

Blakely's killer is finally revealed, but Janet discovers there's someone higher up pulling the strings - someone powerful and very close