A D.S. from the Drug squad is looking for the D.C.I. Cathy recognises him. He is interested in Cathy and follows her on her beat as she checks a domestic. He turns out to be her ex-husband who wants her back. The wife involved in the domestic had been beaten regularly before she stabbed her husband. Quinnan is mouthing off in the canteen and Cathy takes offense. Later Dave wants to patch things up with her. When Dave goes to the hospital he comes across Cathy being threatened by her ex who takes a swing at Dave.