Think carefully. That's the advice Jean Wainwright always gets from her beloved Aunt Constance, Jean's guardian and headmistress at the boarding school where she lives. It's advice that proves valuable when Jean finds herself spending the summer far from home, sorting out family papers for the reclusive Mr. Thiel, a trustee of Aunt Constance's school and the widower of her childhood friend Irene Callender.

At Mr. Thiel's isolated country estate, Jean is surrounded by bewildering questions from the past. Why is there such hatred between Mr. Thiel and his late wife's brother? Was her death an accident? And what happened to their child, who disappeared after Irene Thiel's death? Do the answers lie in the Callender papers? And will searching for the answers put Jean's own life in jeopardy?