Walkthrough for the "Tribes of the East" expansion.

Sorry for interrupting your intelligent conversation... But how do I complete the second scenario as a Necromancer? I defeated the orange and yellow Wizards, completed the quests for the Death Knights and Vampires. I don't know what to do next. The green wall prevents me from entering the red Castle, and I'm also not allowed to enter the southeastern Dungeon; it requires some kind of key. I visited the Red Keymaster's tent and spoke with the Prophet Mage... I have no idea what to do next. It's been four months already :confused: