Frank Trask, a lobsterman who is approached by siblings Alan Townsley and Marjorie French, transports the pair to Cross Island where they search for their mother's grave. They wish to explain the lives of their parents, Vernon and Bernie Townsley. Trask is intrigued by Alan's memories, as they don't ring true and present contradictions. And the utterances of One-eyed Bennie, a local character, confound.

Vernon Townsley and Bernice Jennings were from disparate origins--she the long child of a well-to-do Boston Brahmin--he the son of a Kansas farmer. A graduate of Emerson, she teaches in Augusta, Maine. He seeks to pursue studies at Johns Hopkins but fails to qualify. He works the Baltimore docks and joins the Army. Wounded in France, he meets Bernie at the Togus Military Hospital. Romance is ignited, and then extinguished by anger, followed by Vernon's search for his first love. They meet aqain on Cross Island, marry, sire a family, and endure tragedy.

Trask's search resolves the questions. The spirit of Bernie Townsley, aboard the ghost horse Thunder, guides the children to the grave, where their parents are left in Eternity's Embrace.