Montcalm leaves the French camp before dawn and goes out alone to observe the English fort. He encounters Magua, now a French ally, whose tribe is hungry for scalps. Montcalm tries unsuccessfully to persuade him to drop his intentions, because the French and English are no longer at war. Montcalm fears that he may be unable to control the Indians. At dawn, the English prepare to vacate the fort, according to the terms of surrender. Heyward is anxious to ensure that Cora and Alice will be safe; David insists on singing sacred songs. Heyward informs him that he must protect the two women. The march of departure begins, under the watchful gaze of the French soldiers, who treat the English with respect. The Indians also watch, and only the presence of the French army prevents them from attacking the English. But then a Huron warrior fixes his eyes on a shawl in which an English woman has wrapped her baby. He seizes the screaming baby and dashes its head against a rock. Then he kills the woman with his tomahawk. Magua gives the war-whoop, and other Indians join in. Two thousand Indians emerge from the woods, and a massacre ensues. The English, with unloaded muskets, can offer only token resistance. Munro makes his way to Montcalm to demand protection for his beleaguered force. Meanwhile, David strikes up a holy song. The Indians are impressed by this and leave him and the two women alone. But Magua seizes Alice and makes off with her into the woods. Cora follows, and she is protected by the still-singing David. The Indians now regard him as mad, and leave him alone. Magua finds the horses that Hawkeye’s party abandoned, and Cora and Alice mount one of them. Magua leads them deeper into the forest, and David follows also, taking the second horse. They reach the mountain-top where they had formerly been with Hawkeye, and gaze down at the continuing scene of carnage below.
The massacre at Fort William Henry is the central event of the book, although Cooper does not dwell unduly on the violence of it. He took care to check his sources, and used four different accounts of what happened that day. He also paid a visit to the ruins of the fort.
According to one of Cooper’s sources, fifteen hundred British were killed that day, but modern historians find it impossible to put an exact figure on the number of dead. Later historians have also disputed Cooper’s presentation of the French commander Montcalm as having stood by and allowed the massacre to take place. Other contemporary accounts say that Montcalm did his best to halt the massacre, but to no avail.