Evie was a herbalist, and sentenced to 3 years for murder, a claim she says was untrue. The victim did indeed die, but she blamed it on the fact that the victim didn't listen - they ate an ointment that was supposed to be rubbed onto the skin. Although she managed to impress a few prisoners with her knowledge and skills, Bea Smith was unconvinced, happy to leave that sort of thing to doctors and proper medication.
When inmates and staff started getting sick, the blame was initially placed on Jenny Armstrong, who had a short stay at Wentworth, but was suspected of carrying an illness, as she had returned from Africa prior to her arrest. Eventually it was discovered that the illness was all Evie's doing. She poisoned those who got sick, with the intention of showing them how she could find everything she needed for a cure in the garden.
Evie was targeted with a fire booby trap intended to scare her, however she got badly burnt, and inmate Sandra Hamilton was framed to be the perpetrator. The last we see of Evie is her being taken to hospital for treatment.