Living on the edge of the Pacific ocean, the Callister family and their neighbors had every reason to believe that the Navy yard at Puget Sound would not be safe if there were attacks from forces across the sea.
Lindy is aware that her father draws blueprints of gunwales that fasten guns to the battleships sailing out to the Hawaiian Islands. She is intrigued by the Navy yard, and especially one of the cleaning girls with gold hair. When she learns that Sarah lives in the dark house on the hill, she wants her father to offer her a ride home. The mysterious activities of Sarah's family prove to be alarming indulgences that threaten the "soundness" of the Callister family.