The nurses arrive in Cairo, Egypt (perhaps Ghezireh Red Cross Hospital at Gezira) from Australia and five principal characters are introduced, all depicting real protagonists. Matron Grace Wilson, is seen as a strong leader, but kind and helpful to those under her: Sister Alice is seen to be the strongest of the four nurses; Olive the lovable larrikin; Hilda the shy, religious, uncertain New Zealander; and Elsie Shepherd, an upper-class girl who briefly hides the fact she is married to Lieutenant "Syd" Cook, son of ex-P.M. Joseph Cook. She is depicted as using her maiden name, because as a married woman she would not be eligible for overseas service. (This may be a fiction.)^[5] Each is prepared for a grand adventure, although some seem to have ideas other than nursing on their minds. Alice goes sight-seeing with the gauche Lieut. Frank Smith; meets Major Xavier Leopold, a British doctor, who adores her; and finally Lieut. Harry Moffitt who reads to her from a book of verse and she is smitten. Hilda is among those chosen to join British hospital ship HMHS Sicilia bound for Gallipoli, experiences shelling and tends some of the first casualties, working long hours. Her friend Millicent breaks down.

Matron Wilson and Olive and are among the nurses sent from Cairo to the island of Lemnos to establish a forward field hospital, to care for the less severely wounded from Gallipoli. They have no shelter and little water, limited supplies and grudging recognition from the Australian Army, as exemplified by Colonel Fiaschi, who would send all women back if he had his way. In Cairo, Elsie learns Syd has been seriously wounded, pleads with Matron Gould for leave to visit him at No. 19 B.G.H., Alexandria. She persuades their Matron Oram to get her transferred to the British service, and nurses Syd back to health. Dysentery strikes Lemnos due to flies and lack of sanitation; Matron Jaggard dies and Olive is one of those to suffer, but refuses an offer to be evacuated. She meets an orderly, Pat Dooley, whose company she enjoys.

Harry is wounded and sent to Cairo, so he and Alice meet again. Leopold proposes to her and she is noncommittal, waiting for a sign of affection from the laconic Harry. Syd's recovery is slow, and Elsie argues for him to be sent to England for treatment; she is sent back to Cairo and Oram is not sorry to see her go. Olive's friends Poppy and Lorna are among the nurses returning from Lemnos aboard the troopship Marquette, which is sunk by a torpedo from a German submarine.^[6] Winter arrives and soldiers arrive on Lemnos suffering frostbite. Olive's friend Clarice agrees to marry Sgt Lawrence, just to get off the island. Olive is contemptuous. Fiaschi suffers from beri-beri and is evacuated to Cairo, where the once antagonistic colonel stoutly defends the Lemnos nurses. Troops withdraw from Gallipoli and the five nurses are reunited in Cairo. Elsie volunteers for duty aboard ship Demosthenes taking wounded men back to Australia, where she can care for Syd, but knows she will be barred from serving overseas again.

Elsie is working in a French hospital in Amiens; she knows Syd is back at the Front, but not where. Alice and Hilda arrive at the clearing station and are subjected to air attacks. They are heroic in futile attempts to save patients, then are befriended by a small cat. Elsie hitches a ride to Fricourt to see Syd, who's with 2nd Battalion; back from the Front, he is too traumatised to say much but in a tender scene is bathed and comforted by Elsie. Alice is awarded the Military Medal, presented by Birdwood himself; Major Leopold, with some grace, proposes again and once again Alice refuses, but gratefully. Elsie gets a call from Syd, inviting her to London to meet his parents. She refuses; this time duty comes first; and refuses again when he sees her in person, in a scene that shows him in a less favorable light. Alice nurses some injured German POW's who have been ignored and forgotten. She contemplates the God who is claimed by both sides and becomes fatalistic, while Hilda's faith is reinforced by the fact of her survival. They return to the field hospital and are greeted by Sister Wilson. Following the Armistice and the end of the war, ANZAC soldiers and nurses celebrate in a French town; we are then given a glimpse of the Girls' post-war lives.