In Scotland in the aftermath of the First World War, nurse Esmie McBride meets handsome Captain Tom Lomax at her best friend Lydia’s home. Esmie is at first concerned for Tom’s shell shock, then captivated by his charm, but it’s effervescent Lydia he marries, and the pair begin a new adventure together in India.

When marriage to Tom’s doctor friend Harold offers Esmie the chance to work in India, the two sets of newlyweds find themselves living wildly different lives on the subcontinent. Esmie, heartbroken but resolved, is nursing at a mission hospital on the North West Frontier. Lydia, meanwhile, is the glamorous mistress of the Raj Hotel, where Tom hopes his sociable new wife will dazzle international guests.

As Esmie struggles with her true feelings for Tom and the daily dangers of her work, Lydia realises the Raj is not the centre of high society she had dreamed of. And when crisis strikes both couples, Esmie faces a shattering choice: should she stay the constant friend she’s always been, or risk everything and follow her heart?