A threat hangs over the Space Marines of the Blood Angels. After exterminating all humans in the Red Shard space region, the massive tendril of the hive-fleet Leviathan—like none seen before in the Imperium—moves relentlessly toward Baal. To stand against this terrible enemy, Commander Dante has called upon all the Orders of the ancient IX Legion’s descendants. Sons of Sanguinius gather together, and nothing like this has happened since the dark days of the Horus Heresy. Thirty thousand Space Marines are ready to rise against the Great Devourer to save their Primarch’s home world and prevent billions of lives from being swallowed in the segmentum Ultima lying behind it. But the tyranid swarms are measured in trillions—and they are not the only danger lurking for the Order. The galaxy is rapidly moving toward a dreadful new era. Far away, events are unfolding that could unleash an enormous evil. Descendants of Sanguinius have another enemy as well—the Black Rage that lies in each of them. Can Dante, one of humanity’s greatest heroes, hold back the raging wave? Or will his long rule in the Order end in catastrophe? If Baal falls, the Imperium will be dealt a blow from which it may never recover.