Curse of Naxxramas sends players into the ancient floating necropolis of Naxxramas, which has drifted back to threaten the world. Five wings must be cleared in sequence. The Arachnid Quarter is thick with multi-legged horrors and cunning web-spinners waiting to trap the careless. The Plague Quarter reeks of Heigan the Unclean and worse—every step risks contamination. The Military Quarter forges the useless undead into disciplined soldiers and instruments of war. The Construct Quarter is home to the most extreme experiments in reanimation ever attempted. The final challenge is the Frostwyrm Lair, where an enormous undead ice dragon and the immortal necromancer Kel'Thuzad stand as the last line of defense.