Pre-Siege of Darkness:
Back in Ghost Rider/Blaze, Spirits of Vengeance Issue 16, Ghost Rider, Blaze, and Vengeance defeated Lilith and Zarathos in Cypress Hills Brooklyn. A while later, the Nightstalkers fought a Lilin named Short Circuit. The Darkhold Redeemers just finished defeating a demon called Monstrosity and Jinx started to become Mordred's apprentice. and Morbius feel deeper and deeper to his Lilin side.
The Siege Begins
After that the fight with Short Circuit, the Nightstalkers were called by Blaze, as well as the other members of the Nine(Midnight Sons) to say that Lilith was dead. But the Nightstalkers ain't sure because they couldn't find Lilith's body. They leave the others to the Cemetery to find the both. the Nightstalkers end up in a demonic mist and are attacked by hordes of Lilin including the Lilin Bad Timing. After a small win, the The Midnights sons regroup and separate into two groups. Ghost Rider, Blaze, Sam, Vicki, and Hannibal to investigate the cemetery for Lilith's body, and Morbius, Blade, Mordred, Jinx, Louise, and Drake to investigate the Mist.
Later Vengeance, Caretaker, and Doctor Strange join in with the group. At one point, Ghost Rider. Ghost Rider and Vengeance stopped a crew of Lilin from attacking the police station. Before Doctor Strange could save the Midnight Sons, Ghost, Blaze, and Vengeance are trapped by the Lilins in another dimension and learn of a traitor in the Midnight Sons, Before Lilith and Zarathos attack, The Spirits of Vengeance escape to warn the others of the traitor. But they are to late, at this point, Morbius, who is infected by the Lilith Bloodthirst, kills Louise Hastings and Jinx thinks Mordred is responsible. Moments later that capture Blade, Drake, Jinx, and Mordred.
Elsewhere, The Lilin force are attacking other Marvel characters such as Devil-Slayer, Werewolf by Night, and even the Scarlet Witch.
Meanwhile the remaining Midnight Sons are hiding out a Doctor Strange's Mansion, but the possessed Morbius leads the Lilin inside. As a huge fight goes on, Doctor Strange brings Morbius back to his séances. Morbius save Blade, Drake, Jinx, and Mordred but the Midnight Sons don't see eye to eye right away. At this point Doctor Strange attempts to protect the mansion and those inside, but the mansion is destroyed by a swarm of Lilin including Scatter who was messing with the minds of the Midnight Sons and Sister Nil. After the destruction of the Mansion, the Midnight Sons take refuge in the Nightclub. At this point, Ghost Rider, Blaze, and Vengeance get together at Cypress Hill Cemetery for a final showdown against Lilith and her Lilin. They use the Medallion of Power the send Lilith and the Lilin into the Shadowside Dimension. But Zarathos is back to full power with the Fallen to back him up.
Return of Zarathos
At this point, the Midnight Sons must find remaining members of the Blood to fight Zarathos. During this time, things get more crucial. Ghost Rider loses blood member Patriarch to the Fallen, The Nightstalkers Blade and Drake nearly get killed by the People of the Dust while Hannibal King got into confrontation with Morbius after saving a dying baby Lilin and saving Blood member Rayday from both two Fallen members and the Lilin possessed Martine. Mordred was getting closer to joining the side of Chthon, Caretaker is kidnapped by the Fallen, Victoria Montesi finds out that the is a spawn of Chthon and his pregnant with the elder god and nearly kills herself, Doctor Strange is defeated by renegade Fallen member Salome, and is replaced by a sinister version of him known as Strange, and Ghost Rider is killed by Zarathos.
While this is happening, The Lilin try and use Devil-Slayer's cape to escape the Darkside Dimension.
In the final battle, all that is left standing in battle is Vengeance, Blaze, Caretaker, Morbius, the Nightstalkers, and Strange. As for the Darkhold Redeemers, Vicki Montesi sat out of the battle due to her recent pregnancy, Jinx was in the care of Vicki's father, and Sam Buchanan was in the battle for a little while but left with Stacy Dolan. After finding hidden Blood member Foundry, the Midnight Sons fight the Fallen in South America and defeat them. Majority of the defeat was with Blade requiring the Juciscar Sword given to him by Foundry.
In the end Blade slays Zarathos with a mystical sword defeating him.