In the first episode, Kitty Trevelyan tries to put the troubles of her past behind her as she joins two other girls, Flora Marshall and Rosalie Berwick, to volunteer at one of the busiest war hospitals in Northern France.For the hospital workers, it's a daily battle to patch the men up and keep the war machine churning. Staff numbers are low and the volunteers are desperately needed, yet there are some who see these women as a threat.As the volunteer nurses settle into their first day, it soon becomes clear that no training could have prepared them for the reality of working near the Front Line. Before the day ends, the hospital sees the arrival of Sister Joan Livesey, but it remains to be seen whether her modern approach will be welcomed.