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.
Harry finally tells Marie-Claire that he loves her and the disaster strikes as he goes to save a patient and in doing this he takes a tragic fall. The fall leaves him fighting for his life Meanwhile Johnny tries to come to terms with the loss of a patient. Guy tries to find a reason for this death. Zosia fears she is being sidelined so she takes matters into her own hands.