It is February 1942. Amid the turmoil of World War II, a group of Australian Army nurses, among them Nesta James and Vivian Bullwinkel, have just arrived in Singapore. The women have fled there from Malaya, where they had been stationed to care for Allied troops - and they are reluctant to move on again. Their hope is to remain in the British colony to continue their mission of treating the sick and wounded.

Norah Chambers, an English musician, has also fled to Singapore from Malaya, where she had been living with her husband and her eight-year-old daughter, Sally. A few days earlier she had sent her child away on a ship bound for Australia, desperate to keep her safe from invading Japanese forces.

As the Japanese Army overruns the city, Nesta and Vivian reluctantly join a terrified cargo of people, including the heartbroken Norah, crammed aboard the merchant ship Vyner Brooke. Only two days later, they are bombarded off the coast of Indonesia, and in a matter of hours, the Vyner Brooke has sunk. After 24 hours in the sea, Nesta and Norah reach the beaches of a remote island, only to be captured and held in Japanese POW camps, places of starvation and brutality where disease runs rampant. Alongside hundreds of other women prisoners, they begin a struggle for survival that will last almost four years.

But even here, joy can be found by those with the will to defy their desperate circumstances. When Norah forms a 'vocal orchestra', with the women's voices taking the place of instruments, their music has the power to bring hope into the midst of despair.

Sisters in arms, Norah and Nesta fight side by side, discovering in themselves extraordinary reserves of courage, resourcefulness, humour and hope in their determination to retain their humanity by caring for others.