Catherine was the girlfriend of Robert Preston who passed away young following a drug overdose.
In their teens, Catherine, Robert and Rich Collis worked at the same restaurant. To cope with the long hours the trio began taking drugs - specifically cocaine - however, Catherine eventually suffered from an overdose and passed away. Consumed with guilt at having had been the one to introduce his late girlfriend to the illegal substances - Robert fell into a deep depression but was eventually able to better himself and later began a new relationship with a woman called Jan.
In June 2017, Robert and Rich reconnected - bringing back painful memories about Catherine's death. It transpired that Rich was still involved in drugs and attempted to blackmail Robert into give him cash in order to pay off his dealers - threatening that if he didn't he would inform Robert's partner Michelle Connor about Robert's history of drugs and Catherine's death. Robert refused, and informed Michelle about Catherine himself.