In 1947, photographer and war correspondent Janey Everett arrives at a remote surfing village on the Hawaiian island of Kauai to research a planned biography of forgotten aviation pioneer Sam Mallory, who joined the loyalist forces in the Spanish Civil War and never returned. Obsessed with Sam's fate, Janey has tracked down Irene Lindquist, the owner of a local island-hopping airline, whom she believes might actually be the legendary Irene Foster, Mallory's onetime student and flying partner. Foster's disappearance during a round-the-world flight in 1937 remains one of the world's greatest unsolved mysteries. At first, the flinty Mrs. Lindquist denies any connection to Foster. But Janey informs her that the wreck of Sam Mallory's airplane has recently been discovered in a Spanish desert, and piece by piece, the details of Foster's extraordinary life emerge: from the beginnings of her flying career in Southern California, to her complicated, passionate relationship with Mallory, to the collapse of her marriage to her aggressive career manager, the publishing scion George Morrow. As Irene spins her tale to its searing conclusion, Janey's past gathers its own power. The duel between the two women takes a heart-stopping turn. To whom does Mallory rightfully belong? Can we ever come to terms with the loss of those we love, and the lives we might have lived?