On its way to the Galápagos Islands, a light aircraft crashes into the sea. Zoologist Daniel Kennedy is confronted with a stark Darwinian choice. Should he save himself, or Nancy, the woman he loves? But how can one moment of betrayal ever be forgiven? And after he escapes the plane and swims for help, who is the elusive figure who guides him away from certain death? Back in London, Daniel thinks he finds the answer; it is connected with his great grandfather and the first horrific day of Passchendaele. But as the past collapses into the present, the fissures in his relationship with Nancy show through. Until he is given a second chance to prove his courage and earn her forgiveness.