An armed robbery at a convenience shop reveals an infamous killer has returned to Sydney, and Detective Sgt. Grace Gibbs sets out to catch the culprit behind her colleague's murder.
As Charlie and Grace think they are finally closing in on Tony's elusive murderer, Bo-Lin gets herself entangled in a dangerous crime syndicate while Corey Baxter kidnaps another victim.
Charlie and Grace come to blows over which course to take when they investigate the second murder of the week; Grace finds it hard to ignore Charlie's intuition despite all the evidence pointing to involvement by Corey Baxter.