You can find The Arcatraz dungeon within Tempest Keep, Netherstorm.
The coordinates are (74.3,57.2)
1. Zereketh the Unbound
/i Move out of black circles. Seed of Corruption damages a player & detonates damaging all nearby. Shadow Nova does shadow damage & knocks players back.
2. Dalliah the Doomsayer
/i Run away from Whirlwind. Gift of the Doomsayer curses a player for 10 sec, do not heal this player during this or boss heals.
Heroic Differences: Shadow Wave deals shadow damage to a player & increases their shadow damage taken by 50%.
3. Wrath-Scryer Soccothrates
/i Deals ticking fire damage. Felfire knocks back all nearby players & charges leaving a green fire wall, avoid standing in this.
4. Harbinger Skyriss
/i Releases adds from prisons, final prison is boss. Controls a player to attack allies. 66% & 33% boss creates an illusion of himself to deal shadow damage.
Heroic Differences: Mana Burn takes players mana & deals shadow damage for mana consumed.