The court jester Hop-Frog, "being also a dwarf and a cripple", is the much-abused "fool" of the unnamed king. This king has an insatiable sense of humor: "he seemed to live only for joking". Both Hop-Frog and his best friend, the dancer Trippetta (also small, but beautiful and well-proportioned), have been stolen from their homeland and essentially function as slaves. Because of his physical deformity, which prevents him from walking upright, the King nicknames him "Hop-Frog".
Hop-Frog reacts severely to alcohol, and though the king knows this, he forces Hop-Frog to consume several goblets full. Trippetta begs the king to stop, but instead the king, in front of seven members of his cabinet council, strikes her and throws another goblet of wine into her face, which makes Hop-Frog grit his teeth. The powerful men laugh at the expense of their two servants and ask Hop-Frog (who suddenly becomes sober and cheerful) for advice on an upcoming masquerade. He suggests some very realistic costumes for the men: costumes of orangutans chained together. The men love the idea of scaring their guests and agree to wear tight-fitting shirts and pants 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 the King had insisted the doors be locked; the keys are left with Hop-Frog. 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 Trippetta, 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, grits his teeth again, 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:
I now see distinctly... what manner of people these maskers are. They are a great king and his seven privy-councillors—a king who does not scruple to strike a defenceless girl, and his seven councillors who abet him in the outrage. As for myself, I am simply Hop-Frog, the jester—and this is my last jest.
