The short story by Poe is about a king and his 7 advisers who enjoy practical jokes.  They have enslaved two dwarfs.  One is a male whom they call Hop-Frog and the other is a female who they have named Trippetta.  The king summoned Hop-Frog for advice on a party he was going to have.  The king enjoyed making fun of the dwarf and making him drink wine.  Hop-Frog did not like drinking wine and it makes him drunk very easily.  When the king insists that the dwarf drink another glass, he refuses.  The king becomes angry.  Trippetta falls at the kings knees and asks him to please let Hop-Frog pass up the wine.  The king gets even madder and he hits the girl and throws the wine in her face.

This insult to Trippetta makes the dwarf angry.  He grits his teeth.  He tells the men that he has come up with a joke for them to play on their guests.

"I will equip you as ourang-outangs," proceeded the dwarf; "leave all that to me. The resemblance shall be so striking, that the company of masqueraders will take you for real beasts- and of course, they will be as much terrified as astonished."

The Dwarf coats the king and his advisers with tar, fur, and chains them together.  The king still thinking it is a joke goes along. The "Ourang-otangs" enter the party, scare everyone and while they are wandering in the room the dwarf hooks them to the chain in the center of the ceiling. He then lights them on fire and as they begin to burn he tells everyone

"I now see distinctly." he said, "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."

Hop-Frog gets revenge for being treated badly, for the king hurting Trippetta and throwing wine in her face.  He burns them to death and then climbs out the sky-light.