Save Callum | War

When you're back to the Keep, you'll get message that Callum has been ambushed somewhere along the coast nearby. Hurry to the rescue. Another Shadow Reaver fight is at hand in here. You won't be able to save the brave dwarf. Dead with all the golems, then use the true name scroll on their leader. Take a book from his body - it'll enable you to make the final attack later in the game.

When you go back to the Keep, you can tell Nevalle that your fortress is ready for war. You won't be able to expand it any further from that point, so if you still have some unfinished business, deal with it now. You'll see a cut-scene in which Neverwinter forces led by Lord Nasher are defeated and retreat to the Keep.