In Madness At Midnight you control a gang of deranged cultists trying to summon their Lovecraftian god of choice.
You use action dice to visit different places in Arkham, activate location abilities, and initiate fights with the other players. Your aim is to fulfil sinister plots, defeat the feared investigators, and/or control key locations in order to gain Victory Points. The first player to reach 13 Victory Points wins the game and gets to end the world.
The core of the game is the custom action dice you use to move your cultists and to do stuff in Arkham; learn spells, corrupt the citizens, upgrade your cultists, and more. And the farther you get into the game, and the madder your cultists get, the less chance you have of the dice actually showing the results you need. Madness may be a stepping stone, but it’s also an obstacle you somehow have to manage if you want to be the best cult in Arkham.