The mood is varied throughout the novel. It is often dark and suspenseful, but Cooper interjects humor and merriment every so often to lighten the mood. The protagonists spend most of the novel either in captivity, on the run, or in pursuit of their captive comrades. Encountering danger around every corner puts all the characters on edge. Duncan, who starts out as a confident young soldier who trusts the Iroquois guide he has been assigned, quickly learns that he should always be ready to defend himself against surprise enemies.
At the end of Chapter 21, Hawkeye decides to approach a strange figure. Duncan is so worried that he tries to convince Hawkeye to let him shoot the man. Chapter 22 starts with the delightful revelation that the strange figure is in fact David Gamut, and that the figures all around him are beavers he is trying to baptize. The contrast between Duncan's palpable fear on the one hand, and the comic relief on the other hand once he and the reader realize what they are seeing, is emblematic of the book's regular mood swings.
Cooper leaves the reader on a more somber note, killing off two of the main characters. The final chapter describes Uncas and Cora's funerals and meditates on the end of an era. Although Cora, Uncas, and Magua's deaths resolve the main conflict of the novel and likely render the woods a bit less dangerous for a time, the rest of the characters all seem less carefree than they once did. Chingachgook, for instance, must accept that his only heir is dead and that he will have no living legacy when he dies. The ever-sheltered Alice, meanwhile, has now lived through unimaginable violence and the death of the sister who has been a surrogate mother to her. This loss of innocence seems to be the thing that at last prepares her to leave her father's household to marry Duncan. Cooper ultimately leads the reader to a sense of sad resignation that history has unfolded in the way it has since the time when the events of the novel are set.