PJ is on the trail of a cat burglar known as the Possum. This thief is responsible for a number of jewellery thefts in Mt. Thomas and has proven virtually impossible to catch. PJ enlists Maggie's help but she is having trouble focusing on the case as her thoughts are firmly fixed on her brother Robbie and her discovery that he is using heroin again. Maggie realises that the only way she can help her brother overcome his addiction is with the help of her family so asks their father, Sgt. Pat Doyle, up from Melbourne. Maggie and Pat face Robbie who tries to convince them that he can stop using heroin whenever he likes. Maggie and Pat realise that this is just another junkie line and explain that they will help him any way they can if he is willing to combat his addiction. Robbie suggests that with their help he can go cold turkey. Maggie and Pat decide that they will take shifts in watching Robbie while he goes through withdrawal. However, this makes it even harder for Maggie to concentr