There is shock on Keller when doctor Dominic Copeland returns to Holby to retake his first year. Will Arthur forgive him for what he did to Malick? Mo's sister Adele joins AAU as the new healthcare assisstant but will there be trouble between them? Meanwhile Colette discovers Guy cut corners to give her the nursing job and now she must prove herself to somebody from HR.
Jonny is shocked when Jac prioritises her patients over her daughter on the day of her big operation. Arthur attempts to sabotage Dominic in a bid to get him thrown out of Holby. Meanwhile Mo and Adele clash when Mo pulls rank when they deal with a difficult patient.
New registrar Raf Di Lucca arrives on AAU and makes an impression when he takes on a revolutionary procedure. Sacha comes under pressure from Guy to help Zosia make it as a surgeon and Jac struggles to bond with Emma.
Arthur is undermined by Dominic when they treat a patient with a mystery illness leading to a near fatal situation. Harry's father is admitted to Holby leading Serena to create an opportunity to impress Guy. When Jonny is cut out of the loop by Jac he teams up with Bonnie to make his voice heard.
Under pressure from Raf, Harry desperately tries to find his speciality when he stumbles across a bariatric patient. On the day of Emma's christening Jac is left with a difficult choice when a patient with a rare heart condition arrives at Holby.
Zosia is excited when she gets the chance to treat a psychiatrically vulnerable patient but will her own vulnerabilities be exposed? Harry tries to shake off his bariatric patient who is developing an obsession with him. And when Jac tells Jonny her salary gives her rights over Emma he vows to gain a promotion by exposing her as a bully to Colette.
Jonny faces a tough first day as clinical nurse manager when he has juggle a number of difficult patients and a grumpy Jac breathing down his neck. Guy and Zosia hit another snag in their relationship when she discovers his ulterior motive in allowing her to assist in a transplant operation. Raf continues to clash with Harry over his attitude to medicine.
In an attempt to impress Guy, Dominic takes on a case involving a patient from his past, but what will be revealed? Its Bonnie's 30th birthday but she is forced to re-evaluate her relationship with Jonny when he prioritises his work and Emma before her. Ric reaches out to Jess in an attempt to make up for lost time.
Ric struggles to take a back seat on the day of Jess' operation but when he finds out her husband David is abusing her how will he react? Guy and Zosia clash when she questions his ethics when he operates on a patient in an attempt to keep the Tressler foundation funding. With their relationship under strain Jonny must make a big decision if he is to keep Bonnie in his life.
Ric is in deep trouble after covering for his daughter over the hit and run. When her husband takes a turn for the worse will he stand back or will the surgeon in him take over? Meanwhile Guy and Zosia's relationship hits an all time low when she backs a patients complaint about him. As news of Jonny and Bonnie's engagement breaks the real question is how will Jac react?
New pharmacist Amy Teo arrives at Holby and attracts Harry's attentions unaware that she is already married. To Raf. It is the day of Bonnie's hen night but things turn sour when Jac turns up and questions why she is so desperate to get Jonny down the aisle. Arthur and Dominic continue to clash on Keller but how will they react when the patients are put at risk?
Its the day of Jonny and Bonnie's wedding but will Jac let him go? When they get stuck operating on a patient when he should be at the ceremony and with Bonnie increasingly anxious will the day end in tragedy? Zosia is struggling with anniversary of her mothers death but will she be able to cope?
In an attempt to help Harry pass his assessment Amy covers for him when he makes a mistake diagnosing a diabetic patient. Jac is furious when she leaves Elliot in charge of Emma only for her to go missing. Meanwhile Arthur discovers Jesse and Zosia's relationship.
Jac hears some home truths from her mother on the day of her and Johnny's hearing over Emma. What will she do? Meanwhile Sacha and Estelle grow close after they go to the seaside in an attempt to hide from the press after the story about Joe hits the papers.
Raf discovers the truth about Amy and Harry when he uncovers their lie about the diabetic patient. Elliot is forced to face up to his own medical problems when he treats an eccentric fisherman-cum-singer, whilst Colette warns Jesse off Zosia.
Its the day of Harry's assessment but after the fallout from his affair with Amy will Raf allow him to pass? Jesse cools his relationship with Zosia following a stark warning from Colette and Elliot buries himself away with his Herzig project worried he will run out of time before its completion.
When Jonny announces he intends to move back to Scotland with Emma, Mo makes it her mission to persuade him to stay. Guy offers Jesse a permanent contract but when the truth about his relationship with Zosia comes out will the offer still be on the table? Meanwhile Raf makes a momentous decision about the baby.
Serena's mother has taken another turn for the worse and she finds herself being confronted about it from all sides. A psychologist patient challenges her methods of dealing with Adrienne as her condition worsens, while Guy questions her ability to be a carer and a consultant at the same time, and seems determined to force her to make a choice. Arthur's concern for Zosia's wellbeing spirals with her incessant partying. When his girlfriend Maria is brought in with an infection, he finds that he doesn't even trust Zosia as a doctor when she's in such a fragile state. ...
Fleur and Michael race to diagnose a patient who keeps arresting. However it becomes evident at the end of the day the surgeons are competing more than professionally. A soldier helps cool the strained relationship between Adrienne and Serena.
Zosia returns to the wards of Holby City, but her intensive behaviour forces Guy to ask for another psyche assessment on his daughter. Serena opens up to Raf about her feelings regarding her mother's death. Jac agrees to fund Elliot's protoype for the Herzig.
Zosia's friend, Lisa, encourages Zosia to stop taking her lithium tablets. Afterwards, Zosia treats a male patient, but ends up misdiagnosing him. Then, Lisa pretends to fake her illness to be discharged from hospital, but Jesse is unaware of her unstable condition. Serena argues with the chairman of Holby City.
Raf and Harry's working relationships improves, so Raf asks Amy for a divorce. However, when Amy later goes into labour she gives birth via cesarean. A confident Dominic asks Fleur to go on the Los Angeles list. Jac kisses Guy, while Mo struggles to hide her feelings from Jesse.
Zosia's creepy behaviour endangers her when she is insistent that a dying elderly female patient is her mother. Adele kisses Jesse, causing an awkward tension for Mo when she rejects Mr. T. Amy announces her plans to move back to Singapore.
Oliver Valentine is attacked by thugs outside the ED as he mysteriously returns. When he is rushed up to Darwin Jac discovers he has Chagas disease. Further problems occur as Oliver is also suffering from cirrhosis of the liver, making Elliot's hopeful heart operation tricky. He continues however, using his heart device he's been working on. Ellipt calls the device 'Kibo'.
Dom returns from LA, but when Fleur informs Serena and Ric of his childish behaviour the young doctor begins to question his role on the wards. However, whilst taking a Malick's fiancé back up to the wards from X-ray Dom finds himself trapped in the lift. He manages to perform life-saving surgery in the lift, saving the day. Mary-Claire and Harry spend New Year's Eve together.