Heroes!

The Plaguelands stir.

Above the fetid air looms a terrible evil, casting its shadow over the corrupted soil. Corpses stir from battles past, ripped from their slumber by necrotic magics. The dead return to life, and the plague that once claimed Lordaeron creeps through Azeroth once again.
The Scourge Invasion begins.

It is up to you to drive it back, heroes. From his citadel Naxxramas, Kel’thuzad sends soldiers of the Lich King to every corner of Azeroth. They drift through the sky in Black Necropoli, blistering with undead magic and summoning corpses wherever they fly. You must track down these bastions of undeath and destroy the Necrotic Crystals that power them. Shatter the crystal, slay the Scourge Commander, and destroy the Necropolis.

Treasure and glory await you if you succeed.

The Scourge Invasion has come to Ascension!

Like the Qiraji Invasions before, the Scourge Invasion has been outfitted with several custom Ascension features. To begin, contribution tracking will be returning as a measure of how large your reward is once the final wave and boss is slain. Second, defeating a wave will award all contributing players a scavenged crate based on their contribution, which has a chance to contain all manner of incredible gear. Third, invasion points will appear all throughout the world for all levels: whether you’re leveling up, or already 60, you’ll be able to participate in the Scourge Invasions!

Speak to the Argent Emissary in your Capital City to find a Scourge Invasion near you.
Good luck, heroes.