Betrayal at House on the Hill starts with all players working together as allies, exploring a haunted house filled with dangers, traps, items, and omens. As players journey to new parts of the mansion, room tiles are chosen at random and placed on the game board; this means that the game is different each session. Eventually the Haunt begins, with the nature and plot of this session’s ghost story revealed. One player usually betrays the others and takes the side of the ghosts, monsters, or other enemies, while the remaining players collaborate to defeat them.