Dantalion and Sytry must return to the netherworld when the four Kings of Hell come together for their annual summit.  None among the crowd realize that the Grand Duke Baalberith has secretly sent a horde of demons to the human world to kill William, the Elector who inherited King Solomon's soul.
Tonight is the night when the barrier 
between our two worlds vanishes.
Hoje é noite em que a barreira entre
 nossos mundos se desvanece.