After an incident in which the Indomitable pursues an enemy frigate, Claggart approaches Captain Vere. He tells the captain that there is one sailor aboard who is dangerous. He alludes to the fact that many of the crew are impressed men, and some took part in the recent mutinies at Spithead and Nore. He implies they might be ready to join another mutiny on the Indomitable, and tells Vere he is almost certain that a conspiracy is being mounted, led by this one sailor. Claggart's allusion to the Nore mutiny annoys the captain, although he is not unduly disturbed by Claggart's report. He is not completely convinced of the veracity of what Claggart has told him.
Claggart then names the man he is referring to. It is of course Billy Budd. Captain Vere is astonished. But Claggart says that underneath his pleasant exterior, Budd is a dangerous man.
Vere is surprised because he has a favorable impression of Billy. He admires the way Billy accepted with good grace that he was being forced into naval service. Vere also approves of Billy's performance since he has been on the ship, and was thinking of offering him a promotion.
Vere demands proof of Claggart's accusations, and he warns his master-at-arms that if his report is false, he will be hanged. Claggart replies that he has proof. Vere is apprehensive about what might happen if Claggart's accusation were to become publicly known, so he decides to proceed quietly. He summons Albert, a hammock-boy (a kind of valet) and tells the boy to discreetly inform Billy that he is wanted in the captain's cabin.
Captain Vere, Claggart and Billy Budd meet in the captain's cabin. Claggart looks Billy in the eye and repeats his accusation. Billy is speechless. Captain Vere tells him to speak up and defend himself. Billy, who is astonished at the accusation, struggles desperately to get some words out, but because of his alarm, his speech impediment appears and prevents him from saying a word. Captain Vere, guessing what the problem is, tells him gently to take his time. Billy struggles harder to speak, but still nothing comes out of his mouth. Then suddenly his right arm shoots out and strikes Claggart on the forehead. Claggart falls to the ground and lies motionless.
Vere sends Billy to a stateroom and tells him to wait until he is summoned. Vere sends for a surgeon, who confirms that Claggart is dead. Vere is very agitated and makes some excited remarks that the surgeon finds disturbing. Then he and the surgeon move the body to another room. Vere says he will immediately call a drumhead (emergency) court.
The surgeon leaves the cabin full of misgiving. He does not think the drumhead court is a good idea. He would prefer to postpone action until the ship rejoins its squadron, and then refer the case to the admiral. Disturbed by Vere's strange manner, he wonders whether the captain may be insane.
In these chapters, although they feature the clash between Claggart and Billy Budd that has long been building, the emphasis is really on Captain Vere. Claggart and Billy Budd behave as they must, Claggart motivated by evil, and Billy Budd lashing out in indignant frustration at being falsely accused. The symbolic associations of Billy as Adam, (innocent man before the Fall), and Claggart as the evil serpent are repeated in these chapters, continuing the symbolism that has been established during the course of the novel.
It is Captain Vere whose behavior is now to be put under the microscope. It is he who is put in a morally difficult position, which will test his abilities and his judgment. In chapter 19, Vere's exceptional moral quality is emphasized. He has good intuitions about the essential nature of those he meets, and in the situation he finds himself in he considers his actions carefully. He is prudent and cautious. However, Vere's judgment about calling the drumhead court is questioned by the surgeon (although not to Vere's face), who also raises the specter of Vere's state of mind.
It is clear that Vere believes Billy Budd to be innocent of Claggart's charge. He also expresses his belief that Claggart's death represents the judgment of God against him. His quoting from the Books of Acts (Acts 5: 1-5), confirms this: "It is the divine judgment on Ananias!" In the Bible, Ananias tries to withhold from the apostle Peter some money he has made from selling property. Peter tells him he has lied not to men but to God. When he hears this, Ananias falls down dead. His death is believed by those present to be a judgment of God on his lies.
The ethical and moral question for Captain Vere now becomes, if Claggart was a false accuser, what should become of Billy Budd who killed him? If Claggart deserved to die, and his death is God's judgment upon him, what should be the fate of the man who was acting only as God's instrument? Only a moment after Vere utters the quotation about Ananias, he appears to answer this question: "Struck dead by an angel of God! But the angel must hang!" But as the next chapter will show, the matter is not that simple.