"Slaughter Horse" is a game of murder, horror, and terror, based on the “Mafia” genre of games. In this game, the player is a “captain” who is sent by the Princess of the Sun to investigate reports of dark magic and murder.

The player is the captain of a small ship that has arrived in a quiet little pony town. When the ship arrives, it finds a small village of innocent townsponies, but a large number of Changelings who have taken on the forms of the various inhabitants of the town. The Changelings work together to murder all the innocent townsponies in order to feed their insatiable queen.

The captain is sent to find out what is happening in the town but is soon found to be trapped by the Changelings. The captain is given the task of finding a way to stop the Changelings and save the innocent townsponies.