She has been given a 15 year sentence for trafficking in heroin and Ann is worried at the women's reaction when they find out that Sonia's husband is the police officer who arrested many of the women in Wentworth (Phyllis and Mary Adler are mentioned specifically). Sonia initially pretends that she is inside for blackmailing a politician over a love letter.
Helen Smart recognises Sonia and tells the women she is well known among prostitutes both for supplying them with heroin and for the protection racket she runs with her lover Jerry Turner. Bea's reaction to this news is oddly to urge caution until they know all the facts. Even after Sonia's guilt is established, Bea recommends a war of nerves, though Phyllis takes more phyiscal action, first causing a little "accident" with the sewing machine which gives Sonia a needle straight through the finger and then putting razor blades in Sonia's soap. This last little trick backfires on Phyllis who finds next morning in the shower that her own soap had been spiked (396).
Sonia approaches Joan with a business proposition: she will pay for Joan to arrange her escape. Sonia gets the money in through a visit from Jerry, and Joan tells her she will have her put on laundry duty next day. But the next morning, Joan adds that Jerry has been shot and killed by the police and their stash of money recovered.
Sonia neverthless goes ahead with the escape, though Joan prevents it going ahead so she not only gets the credit but also manages to embarass Colleen as well, as she was supervising the laundry delivery at the time.
Sonia settles down to getting funds together again by running a numbers racket with Phyllis, which attracts the attention of Bea. Joan catches Bea punching Sonia, and sends her to solitary. Sonia tells Bea she intends to take over and suggests to Joan that she could win the women round by getting Lizzie to make illicit booze. Bea is again set up for fighting and sent to solitary where Joan provokes her into an attack which finally persuades Ann to have Bea transferred to Barnhurst. Sonia takes over the press (400).
Sonia's official reign as top dog is only short-lived, and she is dethroned by the unlikely alliance of Cass Parker and Minnie Donovan who make her drink all the illicit booze herself (406). However, Joan has warned Sonia that Minnie could be dangerous, so Sonia recruits another new prisoner Bobbie Mitchell to tape Minnie's conversations with her Walkman. This gives Sonia the idea of taping one of her negotiations with Joan to use as insurance in future.
Brenda Hewitt decides to go into business with Sonia making forged driving licences in the workshop for the Fellowes gang and for payment in drugs (409). She has the tape smuggled out, pretending to Sonia that she has destroyed it, but Joan manages to get the tape back to defuse the threat.
Sonia has a narrow escape from killer screw David Bridges when he agrees to arrange her "escape". Fortunately, Randi Goodlove takes Sonia's place and is killed insteads of her (414).
Meanwhile, a blind prisoner Belinda Johns has been admitted to Wentworth, and it is eventually revealed that she is behind the series of assaults on Sonia of increasing severity - ground glass is added to Sonia's hand cream (418); she is stabbed in the back with a piece of her broken mirror (420); Belinda attempts to strangle her with the flex of her kettle (425). Finally, Belinda corners Sonia in the library, and tries to attack her with a spanner when the lights are suddenly switched off (427), but she cannot finish Sonia off.
Sonia suspects that it was the new officer Rick Manning who switched out the lights, as she knows that he used to be in the police force with her husband Eddie. With the introduction of the suggestion that Sonia's husband Eddie might have been as bent as she was, or even more so, the crosses and double crosses proliferate until at some points the story hardly makes sense any more.
A new prisoner, Meryl King, pals up with Sonia and confirms that Eddie is on the take (429), but when she is released it seems that she was deliberately planted (by who?) to feed Sonia with false information about Eddie and the circumstances that led to Rick Manning leaving the police.
Presumably Meryl is also responsible for the dummy hanging found in Sonia's cell, but not for the snake that is indavertently brought into the prison by Cass, which terrorises Sonia so much that she is found one morning crouched on top of the sink unit in a trance (433). She sees Dr Weissman, which gives her the opportunity to tell him (and us) about the circumstances of the death of her baby.
When Sonia is well enough to come out of the infirmary, she moves in with Myra Desmond who has just been brought to Wentworth (435) and plays on her sympathy so that Myra takes her side against Joan. She tells Myra tells her about her lover Nick who punched her in the stomach when she was seven months pregnant after she refused to have an abortion. Joan overhears and plants a bloodstained doll on Sonia's bed, though this only increases Myra's sympathy for Sonia.
After attempts on Rick Manning's life from members of the Fellowes gang, Eddie admits to Rick that Lionel Fellowes had asked Eddie to kill him. Shortly afterwards, Sonia is told that Eddie has been killed in a car accident, so she suspects it must have been Rick who arranged it, and an associate of Fellowes visits her to offer his "condolences" and increase her suspicions of Rick (439).
In fact, Eddie's death had been faked to allow him to go undercover to try to nail two corrupt police officers Mears and Birmingham. They visit Sonia to "question" her, and one of them gives her cyanide to poison Rick. Sonia tricks a new prisoner Gloria Payne to put the poison in Rick's food, telling her it's a "laxative" powder, but the glass of milk she puts it in is split by Cass before Rick can drink it.
Sonia's "mother" visits: she is really a contact from Fellowes who tells her she will be sprung from Wentworth (440). And indeed a directive comes to Wentworth that Sonia is to be transferred to Barnhurst along with Bobbie: however, on the way to Barnhurst, the "police" driver pulls a gun on them and backs the car into a waiting van in a layby.
Sonia soon finds out that she has been kidnapped not by the Fellowes gang, but by a Sydney-based gangster Kurt Renner, who intends to use her as bait to get Eddie onto his patch to settle a score with him (Eddie once dared to shoot him in the leg). With scarcely a moment to take in the news that Eddie is still alive, Sonia's instinct for self-preservation surfaces and she asks to join Renner's operation after he's dealt with Eddie.
Sonia suggests that Renner uses Bobbie rather than her as bait: by putting Bobbie to work as a prostitute, Eddie will be able to trace her instead when the police find out they are in Sydney. It is implied that Sonia is partly trying to keep Bobbie alive by making her survival essential to Renner's plan. Eddie traces Bobbie (445) and gives her a message to pass back to Sonia. Before she can do so, one of Renner's thugs finds Eddie's contact number in Bobbie's handbag and Renner makes Sonia phone Eddie to arrange a meeting.
Joan Ferguson throws a temporary spanner in the works by recognising Bobbie on the streets when she is in Sydney to visit her father and makes Bobbie contact Sonia to try to recapture both of them single-handed. Sonia agrees to come next morning, but first she goes to meet Eddie as arranged and watches impassively as Renner shoots him (447). To keep her rendez-vous with Bobbie, Sonia has to slip out of Renner's bed after knocking him out with the butt of his own gun.
Sonia is furious at the prospect of being recaptured and manages to trick Joan and escape: she is last seen with her car parked on the edge of a cliff looking out to sea, then down to the rocks below...
When her car is discovered, Sonia is nowhere to be seen, and there is a bullet hole in the windscreen.
The mystery of Sonia's ultimate fate is never settled explicitly. I suppose nothing we see is inconsistent with her faking her own death and making an escape, but I think we are supposed to assume from the scene in (447) where Eddie (who has cheated death a second time!) leaks her probable destination to Mears and Birmingham that they had tracked her down and killed her.