"Duffy" worked as staff nurse in Holby A&E from the first series. She wasn't too serious about her work to begin with; she enjoyed having a laugh with receptionist Susie Mercier. She was raped one night on her way to work; she was unable to talk to anyone about it straight away and she decided not to tell the police, but she later confided in Megan Roach and these two became good friends.
By series 2 Duffy was staff nurse. She had a relationship with salesman Peter Tranter; they were going to go to America but he found out he was HIV positive and left her. She had a test but it was negative. Duffy later found out that Peter had died.
Duffy was promoted to sister at the beginning of series 4. A brief affair with Dr. Andrew Bower left her pregnant. Andrew offered to marry her, but she turned down his proposal, saying she didn't love him, and started to bring up her son Peter alone. She found it hard work and felt she was missing out on her son.
In series 7 Duffy was called back after a routine smear test. She was worried about cervical cancer. Sandra Nichol told Julian Chapman, who pulled some strings so she could jump the queue for the next test and find out. The news was good.
Andrew returned to Holby A&E as locum when Julian Chapman left. She agreed to let him see Peter and they started their relationship again. This time when Andrew proposed she accepted, and they were married just after the end of series 7.
Duffy was always good friends with Charlie Fairhead, but they argued a lot in series 8, starting with a misunderstanding on her part about his relationship with Kenneth Hodges, and getting worse when he was the last to find out when she became pregnant again and decided to leave. However, they made friends again on her last day.
When Duffy returned for Charlie and Baz's wedding, she told Megan that she was now doing agency work. She also revealed that she was having marital problems after Andrew had a one-night stand.
When Charlie needed an agency nurse in series 13, who else would he call on but Duffy? She returned and later applied for and got the post of senior staff nurse. She confessed to Charlie that she had found out that Andrew's one-night stand wasn't just that; Andrew was still seeing the woman.
Duffy had a good friendship with Max Gallagher. After the departure of Eve Montgomery, Duffy applied for the sister's post. During the interview, Max gave her a hard time. When she later complained to him, he said he didn't want anyone thinking he was biased. He told her she'd got the job. They kissed...
Charlie found out about the affair and told Duffy to think about what she was doing, to think about her kids - he said she was risking losing everything. Duffy was angry with him for interfering, but finished things with Max. She later apologised to Charlie, saying he had been right, and they were friends again.
Duffy got a shock in series 15 when Andrew told her he'd be working at Holby A&E for a while as Broadway General would be closed for refurbishment. She was worried about Max and Andrew working together but Max assured her that they would be professional about it, and that Andrew wouldn't find out. Another shock came for Duffy when she realised she was pregnant. When she told Andrew about it she found out that he didn't want another baby, but decided she was going to have it whether he liked it or not. A miscarriage scare made Andrew realise he wanted the baby, but he and Duffy were still not getting on well until Duffy found out he had turned down a consultant's post because he didn't want to tread on her territory and risk messing up their marriage. They were playing the loving couple from then on. Duffy took her maternity leave. In the last episode of the series her world was turned upside down when Andrew died after being pushed down some stairs.
At the beginning of series 16 when Charlie was visiting her, Duffy told him she wasn't sure she wanted to go back to work in the place Andrew died. Soon afterwards she went into labour, and as she didn't want her baby to be born in the hospital where its father died, she begged Charlie to deliver it, and her third son, Paul, was born. A few weeks later she decided she would return to work, thinking it's what Andrew would have wanted. Her first day back was tough, but she soon seemed to be back in the swing of things, and according to her colleagues, was inheriting Megan's "Mother Earth" mantle.
At the beginning of series 17, Duffy was upset by a cheque for £300,000 from Andrew's life insurance. She wanted to send it back, saying Andrew was worth more than that, but Charlie persuaded her to keep it for the sake of her sons. Duffy got another shock when she realised that her mother had been brought into A&E, and that Charlie, abiding by her mother's wishes, had kept this from her. It turned out that her mother had untreatable cancer. Duffy told Charlie that two rocks had kept her going over the last couple of years - him and her mother, but now one was dying and the other she couldn't trust. Soon afterwards her mother was brought into A&E again. When Duffy arrived, Charlie told her that her mother had asked not to be resuscitated if she had another fit. Duffy begged her mother to change her mind, but her mother was adamant, and when she fitted again, Charlie accepted her mother's word and the team would not resuscitate her. Duffy shrugged off Charlie's comfort, and new security guard Ryan Johnson went to comfort her, able to empathise because his wife had died of cancer. After Duffy returned to work, Ryan asked her out, and Duffy agreed. Later, however, she changed her mind, feeling she wasn't ready to see anyone, but accepted Ryan's offer of a lift to the prison to see Lara. Duffy was upset after the visit, and determined to go to see Melanie Collier to try to persuade her to give evidence at Lara's appeal. She did so with little success, but when Melanie later came into A&E, still suffering from injuries caused by her dead husband, Duffy managed to convince her to tell the truth, for the sake of her children.
Ryan supported Duffy through her ordeal with Melanie, and they quickly became an item. Ryan suggested they should start a business together, to allow Duffy more time to spend with her children. Duffy agreed, and handed in her notice. When Ryan asked her to marry him she said yes straight away. But the day after she left her job, Ryan disappeared, taking all of Duffy's money and leaving her in severe debt. Trying to rebuild her life again she took up agency nursing. She was forced to sell her house to pay off her debts, and when she struggled to find somewhere to live, Charlie invited Duffy and her family to move into his house. Soon afterwards, however, Ryan turned up again. He admitted he was a con man but said that this time he really had fallen for Duffy, and that he loved her. He offered her a new life in New Zealand, and Duffy, realising she loved him, agreed, on condition that everything was in her name. She said goodbye to Charlie once again and set off to a new life.