Beyond That, the Sea follows the story of two families on two different continents, separated by the sea but united in their love for one person: Beatrix. She spends part of her childhood with the Gregorys in the US, sent there by her own parents to protect her during the war, and these years prove formative and significant. She forms a lasting link with the family and the country, and even after she returns home to London, she struggles to reconcile her identity as shaped by her time in the US. This becomes one of the novel’s central themes.

Although the circumstances under which Beatrix goes to the US aren’t pleasant, she experiences some of the happiest times of her life with the Gregorys. She’s immediately taken in by Gerald and Nancy’s warmth and openness, smiling at Gerald’s welcome on the dock and allowing Nancy to give her a bath that same evening. Bea forms unique and special bonds with each member of the Gregory family: Ethan teaches her how to swim and play chess, she and Nancy have their special bath-time ritual every night for years, and both William and Gerald are her close friends and confidants, her relationship with William eventually even developing into a romance.