Because the pistols are old and have not been primed or cleaned for a long time, Deerslayer suggests that he and Chingachgook practice firing them. Deerslayer proves his superior marksmanship, but his pistol explodes accidentally — exactly what he had feared because of Hutter's long neglect of the loaded weapons. No one is hurt, but Judith is very frightened by the incident. They continue their search of the chest where they find a sextant, another proof that the uneducated Tom Hutter was not the original owner of many of the items, and finally some carved ivory chess pieces. These figures, for the first time, evoke a surprised response from the usually stoical Chingachgook, and Judith joins the Indian in admiration of the delicately wrought pieces. Deerslayer, however, is singularly unimpressed, and becomes very serious and concerned. He finally states his cause for anxiety: He believes that the figures are idols which Tom Hutter has worshipped. Indeed, the apparent evidence of paganism almost repels Deerslayer from attempting to rescue the captive. Judith, explaining that she has seen officers at the fort playing a game with the figures, convinces Deerslayer of his wrong interpretation when she finds the chess board. The group agree that some of the chess pieces (rooks in the form of elephants) can be used to bargain with the Mingos for the prisoners' release.
The sound of steps surprises the group, and Hetty's appearance with an Indian stuns the three people. Deerslayer quickly makes Chingachgook hide. Hetty, telling about her adventures among the Mingos, believes that the Indians are willing to attend church services aboard the ark. Judith and Deerslayer are skeptical. Noticing the poorly constructed raft in which Hetty and the Mingo guide arrived, Deerslayer realizes that the Indians are in no position to attack the ark. He shows one ivory chess piece, a rook (castle) carved like an elephant, to the Mingo, who is elated by it. Deerslayer explains that two of these figures will be given in exchange for the prisoners. The Mingo departs happily with the message, and Deerslayer ponders about possible arguments in the coming negotiations. Hetty's news about Hist makes Chingachgook optimistic about rescuing the Indian girl: Hist will be waiting at the place where Hetty landed on the previous night, and Chingachgook should come for her about an hour after dark.
Chingachgook takes off his white man's clothes and stands proudly on the deck in his rightful image as an Indian. Anxious to see Hist, Chingachgook proposes to go in person to the Mingo camp as an emissary, an offer which Deerslayer immediately rejects as being motivated by emotion rather than by reason. Despite their hopes that the Mingos will negotiate for the prisoners' release, the defenders of the ark take no chances and prepare defenses. But the raft appears with two Mingos. Rivenoak, the chief, and Deerslayer discuss terms, and the Indian is visibly moved by the latter's directness and honesty. Deerslayer, for instance, tosses one of the ivory pieces to Rivenoak for inspection although Hawkeye, as he now identifies himself to the Mingo leader, warns that he will shoot if the piece is not returned.
The negotiations drag on, the Indians haggle for more than two chess pieces, and Deerslayer insists that his first offer is a fair bargain. The discussions are close to failure, and Judith warns Deerslayer that one of the Mingos is reaching for a rifle hidden in the bottom of the raft. Deerslayer, however, is on his guard, and Rivenoak continues talking about an agreement. Deerslayer quickly takes advantage of this critical moment: He proposes that, if the Indians bring the prisoners, they can keep the ivory token already in their possession, with two more chess pieces added for the bargain and an extra one for speed in returning the captives. The Indians, overjoyed by this generosity, leave hastily, and return before sunset with Tom Hutter and Hurry Harry.
Deerslayer, of course, keeps his promise about the bargain; but Hurry Harry is no sooner on board the ark than be seizes Deerslayer's rifle to shoot the Indians. Fearing this reaction from the impetuous Hurry, Deerslayer had asked Judith to hide all the other firearms; Natty wrenches his own gun from Hurry's grasp. A shot is fired into the air without any harm done. After the Mingos return to the shore, the exiles on the ark sit down to eat, exchange information, and discuss their situation.
Some humorous scenes and dialogue interrupt the serious problems of the captives and the investigation of the chest's contents. The friendly shooting contest between Deerslayer and Chingachgook, while confirming the former's prowess, proves amusing as Chingachgook's bullet lands harmlessly in the water. But the next joke is on Deerslayer as he mistakenly considers the chess pieces as pagan idols. His long soliloquy about the degradation of such worship and the higher nature of Christian belief in one God is an explanation of Natty's faith and religious training. However, the effect is also a parody of the smug and righteous attitudes of Christians who can be very incorrect in their interpretations and conclusions. Cooper, concerned about Christianity facing an alien culture, is clearly on the side of charitable, liberal readings of the Bible and dogmas. He likewise condemns hypocrisy and ignorance and Natty's vehement outbursts — not in harmony with his usual character — are farcical in their erroneous analysis of the ivory chess pieces.
Ironically, Judith scores one of her few victories over Deerslayer's ideas in this episode of the chess set. But some of the sad facts about Judith's mother also begin to come to light. Unfortunate and mysterious experiences are evidently involved in the life of this woman whom Tom Hutter, it was previously learned, buried in the lake.
A bond of sympathy and understanding has been formed between Hetty and Hist, and the former's admonitions to Chingachgook about his future behavior toward his betrothed show Hetty's gentle nature and, at times, wise reactions.
The plot has taken an important turn for the better: The ransom for the captives has been found in the chest; and the Indians, after suspenseful and uncertain negotiations, consent to the exchange of prisoners for the elephant-shaped chess pieces. There are now six defenders of the ark, their position is secure, and the Mingos have still not found the means to attack these defenses from their positions on the shores of Glimmerglass. But another visit to the shore — to the exact place where Hetty landed — is indicated by Hist's words to Hetty, related in turn by the latter to Chingachgook. Thus Cooper, in solving one plot complication, prepares his readers for another adventure.
The bargaining between the Indians and Deerslayer is a model of shrewdness and give-and-take on both sides. Cooper makes the point very definitely that the Indians' first astonishment and increasing trust in Deerslayer's fairness has not been the normal procedure in relations between the natives and the white men. In fact, Cooper, by emphasizing the exemplary character of the negotiations, is strongly criticizing historical fact and is indicating his theories about the proper conduct of his own race. Although the Mingos are not above treachery as a device to be employed whenever it might gain the victory, Cooper defends this procedure as part of the Indian code. The use of "sarcumventions" is permitted to the natives as an element of their "gifts," which, despite objections from their foes, are lawful. The vengeful code of Hurry Harry — and Tom Hutter if he had been physically able to act — is no better than that of the untrustworthy savages. However, Cooper insists that the white men, because of different "gifts" (among which is Christianity), cannot resort to such acts of barbarism. The white men must adhere to nobler principles; otherwise they bring shame, disgrace, and disaster upon themselves when they indulge in atrocities, such as scalping and attempting to shoot the Indians in the back.
Cooper, then, uses contrast to reinforce his philosophical and social ideas: Deerslayer's honorable and Hurry Harry's reprehensible dealings with the Indians; Deerslayer's and Judith's interpretations of paganism and Christian beliefs by means of the chess figures; and Deerslayer's and Chingachgook's claims to white or native superiority — though in jest — in the use of guns. Hetty, relying upon intuition rather than reason, is again offered in contrast to her sister and to Chingachgook to whom she must relate news from Hist. The six — although mutually dependent on one another — are, nevertheless, opposed in various ways. Obviously, Deerslayer and Chingachgook, although of different "gifts," form a team (representing the good and noble) against the pair of Tom Hutter and Hurry Harry (symbolizing greed and corruption).