Sonia is the wealthy but self-made dynamo behind a cosmetics empire that was owned and run by her late husband, Geoffrey Stevens. Then Geoffrey disappeared. As far as the world knows, Geoffrey is suspected of suicide after a devastating cancer diagnosis. When Sonia’s best friend Helen Masters also goes missing, the police are suspicious and have gathered enough circumstantial evidence to charge her with murder.
Liz Birdsworth is put up to the task to retrieve evidence finding out clue's to try and make Liz look good with Vera, but Sonia declines any information coming forth.
While cutting Maxine's hair, she delivers a cryptic message that she may have had something to do with the murder (referring to cutting hair as taking a crown away).
Initially friendly towards the crew, things get rocky between them after Sonia discovers that "Witness X" is an inmate which causes her to speculate Maxine.
Sonia is also a victim of Lucy Gambaro (Juice) as she is bashed in the showers after Lucy trying to convince her to donate money to her which she ultimately fails and then demonstrates why she needs there protection. She is put in a wheelchair for a few days when Joan Ferguson (The Freak) cuts out Lucy' tongue she soon becomes top dog.
- Sigrid Thornton appeared on the original Prisoner as Ros Coulson
- Sigrid is currently the only actress of Wentworth to have been in the original show.
- Sonia is similar in some ways to Ros, both were convicted of murder (Albeit under different circumstances) and both are shown to be highly intelligent.
- Sonia is very different to her original series counterpart, the original Sonia Stevens was a drug dealer who specialised in fleecing and supplying prostitutes.
|Wentworth: Season 4|
|"Love and Hate"|
|"Divide and Conquer"|
|"The Eleventh Hour"|