Hop-Frog has severe reactions to alcohol and, though the king knows this, he forces Hop-Frog to consume several goblets full. Trippetta begs him to stop and, in front of seven members of his cabinet council, he strikes her and throws another goblet of wine into her face. The powerful men laugh at the expense of their two servants and ask Hop-Frog (who has very suddenly sobered up and become cheerful) for advice on an upcoming masquerade. He suggests some very realistic costumes for the men of orangutans chained together. The men love the idea of scaring their guests and agree to wear tight-fitting shirts and pants, which are then saturated with tar and covered with flax. In full costume, the men are then chained together and led into the "grand saloon" of masqueraders just after midnight.
As predicted, the guests are shocked and many believe the men to be real "beasts of some kind in reality, if not precisely ourang-outangs." Many rush for the doors to escape but Hop-Frog has insisted the doors be locked and the keys given to him. Amidst the chaos, Hop-Frog attaches a chain from the ceiling to the chain linked around the men in costume. The chain then pulls them up via pulley (presumably by Tripetta, who had arranged the room so) far above the crowd. Hop-Frog puts on a spectacle so that the guests presume "the whole matter as a well-contrived pleasantry." He claims he can identify the culprits by looking at them up close. He climbs up to their level, and holds a torch close to the men's faces. They quickly catch fire: "In less than half a minute the whole eight ourang-outangs were blazing fiercely, amid the shrieks of the multitude who gazed at them from below, horror-stricken, and without the power to render them the slightest assistance." Finally, before escaping through a sky-light with Trippetta to their home country, Hop-Frog identifies the men in costume: After this, Hop-Frog and Trippetta make their escape.
The story uses the grating of Hop-Frog's teeth as a symbolic element, just before he comes up with his plan for revenge and again just after executing it. Poe often used teeth as a sign of mortality, as in lips writhing about the teeth of the mesmerized man in "The Facts in the Case of M. Valdemar" and the obsession over teeth in "Berenice".
Just as "The Cask of Amontillado" was Poe's attempt at literary revenge on a personal enemy, "Hop-Frog" may have had similar motivations. As Poe had been pursuing relationships with Sarah Helen Whitman and Nancy Richmond (either romantic or platonic is uncertain), members of the New York City literary circle spread gossip and incited scandal about alleged improprieties. At the center of it was a woman named Elizabeth F. Ellet, whose affections Poe had previously scorned. Ellet may be represented by the king himself, his seven councilors representing Margaret Fuller, Hiram Fuller (no relation), Thomas Dunn English, Anne Lynch Botta, Anna Blackwell, Ermina Jane Locke and her husband.
The tale, written toward the end of Poe's life, was somewhat autobiographical in other ways. The jester Hop-Frog, like Poe, was "kidnapped from home and presented to the king" (his wealthy foster father John Allan), "bearing a name not given in baptism but 'conferred upon him'... and susceptible to wine... when insulted and forced to drink becomes insane with rage". Like Hop-Frog, Poe was bothered by those who urged him to drink, despite a single glass of wine making him drunk.
The story may also have been inspired by a historical event, the Bal des Ardents, at the court of Charles VI of France. At the suggestion of a Norman squire, the king and five others dress as satyrs in highly flammable costumes made with pitch and flax. Four of the men died in the fire; Charles was saved.
"The Murders in the Rue Morgue" also concerns an orangutan, although in that story the ape is real.