As the sun sets over 1968 Australia, sisters Gail and Cynthia set off towards the town square, eagerly rehearsing their harmonious voices in preparation for a talent contest. Unfortunately, their younger sister Julie, weighed down by her youth and responsibilities as a young mother, is barred from joining them. Refusing to be left behind, she cleverly seeks help from a neighbor, ultimately finding herself on stage alongside her sisters.
Simultaneously, Dave Lovelace, an Irish talent scout attempting to shake off the remnants of a hangover, is unexpectedly called in for a meeting with his boss. Just having rolled out of bed, he faces serious admonishment for his habitual tardiness, a reflection of his night-long escapades. This fateful interaction introduces him to Gail and Cynthia, whose awe-inspiring performance goes unnoticed by the judges, leaving them disheartened by the remark: >“Pack it up, girls - you're not cut out for the big leagues.” Yet, Dave sees the sisters' undeniable talent and realizes the precious opportunity before him.
As news of their potential spreads rapidly, Gail and Cynthia are quickly swept away to Melbourne to audition for a chance to entertain the troops in Vietnam. Their mother is fraught with worry about their safety in a foreign land, but the sisters, driven by determination and a thirst for adventure, are resolute in grabbing this opportunity.
Back home, whispers about their journey create a buzz that attracts various family members and friends, including Kay, a cousin shaped by her painful past with the government's harsh treatment of half-white children, known as the Stolen Generations. Though initially hesitant to accompany her sisters, the combination of family bonds and the magic of music ultimately win her over, leading her to join Gail and Cynthia at their uncle's place.
As days pass, the trio adopts the name The Sapphires—inspired by Cynthia's now-irrelevant engagement ring—while refining their musical skills and blossoming together. However, the bond among the sisters begins to fray as Gail takes on an overprotective matriarch role and Cynthia entertains a romantic interest within their military escort. At the same time, Kay grapples with her dual identity, contending with both her Indigenous roots and the label of being a "half-caste," while navigating the affection of an Army medic.
Julie, still reeling from her recent broken engagement, struggles to comprehend the harsh realities of war. As The Sapphires gain popularity, the tension between Gail and Dave simmers, particularly as Gail's patience is tested by Dave's reckless ways and a profound personal secret. When The Sapphires arrive at a highly anticipated venue without military accompaniment, Julie's incredible singing talent captures the attention of a distinguished U.S. talent scout. Meanwhile, Cynthia's discontent escalates, prompting her to indulge irresponsibly during their initial set, alarming her sisters. Gail steps in, firmly reminding Cynthia that such behavior is unacceptable. Amidst the brewing tension, Dave discreetly hands Gail a letter, advising her to read it later. Just as they share a moment charged with potential romance, chaos erupts as the base is suddenly attacked.
In the ensuing turmoil, Dave focuses on ensuring Gail and Cynthia's safe evacuation via helicopter, before rushing back to rescue the remaining band members, only to be struck by gunfire. Gail watches in horror as her concern for Dave's safety clamors against her instinct to reach him. Meanwhile, Kay and Julie secure places on Kay's boyfriend's medical evacuation helicopter, only to face racial hostility from a dying white soldier.
Once in Saigon, Gail finds comfort in Dave's letter, only to discover that he had intended to propose to her. Amidst the grim circumstances, they are invited to perform that evening following the tragic assassination of Martin Luther King Jr. Gail takes the stage, her voice resonating with raw emotion as she channels her grief into song. News of Dave's recovery arrives, carried by Kay's boyfriend, along with the hope of a swift journey back to Australia, where The Sapphires can regroup and realign their ambitions.
As they chart their next chapter, Gail and Dave joyfully announce their engagement to her family, surrounded by a profound sense of celebration. The Sapphires gather with friends and loved ones in their backyard, performing vibrantly as they intertwine their voices, celebrating their journey and the triumphs that have marked their lives.
