Hetty's death is a melodramatic moment at the book's end, lending more poignancy and tragedy to Judith's sister who has already suffered a great deal in life. Hetty, who is in love shyly and really unknowingly with Hurry Harry, realizes that she does not possess normal, human intellectual powers. However, Hetty is not an idiot, nor is she mentally retarded to the point of being useless. Hetty is limited in her ability to follow detailed and complicated arguments, but she can and does prove to be diligent and efficient in many tasks. She is very sharply depicted as the antithesis of her sister, Judith, and the contrasts between the two girls are evident, from Deerslayer's meeting with them early in the book to the death scene of Hetty after the battle.
Cooper illustrates his moral, religious, and philosophical ideas very clearly in the picture he draws of Hetty. She relies completely on the Bible for her conduct and ideas. Hetty's inability to engage in any complex discussion makes her a very literal believer in Biblical teachings. She reads and interprets the Gospel without question, and she asks of the white men and the Indians that they equally accept her own strong, unwavering faith. Cooper, through the character of Hetty, poses some of his most serious questions about the American experience: Can the teachings of Christianity be applied to the relations between the pioneers and the Indians? How is the exploitation of the natives justified in view of Christian morality?
Hetty, representing simplicity, honesty, and innocence, is always the voice of morality who speaks out against violence and bloodshed. She criticizes not only the Indians but also her white companions on the ark for their reliance upon power rather than the words of the Bible. Deerslayer is not exempted from Hetty's accusations, and he tries on several occasions to explain to her the need for practicality in the perilous frontier encounters. Hetty, depending upon the truth of the Gospel, is saved from death by the respect of the Indians for her mental limitations rather than any influence of Christianity upon them. Hetty's accidental death shows that her innocence and credulity fail in a world devoted to action and violent confrontations, although she stands out as a symbol of goodness and exemplary conduct for all who have known her.