D.I. Shawnee Hudson was a detective who, alongside undercover officer Simon Walker, investigated gangster Brendan Brady in 2012. In August 2012, Brendan and Walker carried out a drug heist on Sampson's incoming shipment, only to be swarmed by police. After Walker shot an officer (intending to hit his bulletproof vest), Shawnee confronted Walker and told him that he was no longer allowed to investigate Brendan. Walker, however, managed to talk her round.
After Mick Cornus fell from a lighthouse whilst being hung from it by Brendan, Walker suffocated Mick to death to frame Brendan and told Shawnee about his body being in Brendan's car boot. Shawnee searched Brendan's car, only to find it empty. An enraged Shawnee gave Walker 24 hours to find incriminating evidence, but allowed him more time after finding a shaken Walker, who had been forced to sleep with Brendan to remain undercover.
In October 2012, Shawnee visited Walker and demanded that he dropped the case. Walker then proceeded to beat Shawnee unconscious and left her by the side of the road. In November 2012, Shawnee managed to convince Doug Carter to secretly work with Walker, but Doug backed out after Doug's boyfriend Ste Hay (and Brendan's ex-boyfriend) was injured in a bus crash.