"While hijacking one of Yondu's Ravager ships with the assistance of Cosmo and Phyla-Vell, Adam Warlock is able to break through Odin's barrier and arrive on Earth. However, Adam is lost in the resulting crash landing, only to resurface as Magus his evil alter ego. In this worse case scenario can S.H.I.E.L.D. eliminate Magus while saving Adam as the Serpent threatens to tear apart the world as we know it?" — Chapter Briefing
The only way to recruit Adam Warlock is to complete the list of Tasks.
Two of the Tasks require the defeat of an Epic Boss. This can be done by having the requirements needed to unlock the Epic Bosses or by skipping the tasks by paying 5 Gold each.
The requirements are:
"Adam Warlock, Cosmo, and Phyla-Vell manage to slip past Odin's Barrier in one of Yondu's Ravager ships, but they crash land in the Savage Lands while being pursued. Cosmo contacts the Guardians telepathically, informing them of their situation, but they have lost Adam somewhere in the Savage Lands in the crash. Making matters worse, Yondu is still pursuing them for revenge, least of all for being trapped on Earth..." — Mission Preview
"Magus has emerged from his Cocoon and openly threatens the Serpent and his Worthy while claiming that he can bring down Odin's Barrier. All those who wish for his "divine assistance" should come to his aid as he prepares to destroy the Barrier. The Mandarin struggles to retain control over Madripoor while it falls into chaos as villains of the world unite under Magus's reign." — Mission Preview
"Cosmo proposes a plan using the combined telepathic might of Earth's heroes to break into the Magus's mind and free Adam, and not a moment too soon as Magus prepares to "break" the barrier. Strangely, the Serpent and his Worthy haven't seemed to react much to Magus's threats, but the actions of the Circle of 8 have been on the rise. Magus's allies gather in New York where Magus is confronted at last only to learn a horrible truth." — Mission Preview