Calamity (2016)

Calamity is a 2016 fantasy novel written by American author Brandon Sanderson, released in 2016 as part of theReckoners series. It was preceded by the novels Steelheart, Firefight and the short story Mitosis.

Plot Summary
After the events of Firefight, Abraham, Cody, Megan, and David are now all that's left of the Reckoners. The role of leader of the Reckoners has now fallen to David. Prof has been swallowed up by the darkness of his powers and has begun to take over a city and recruiting his own minion epics. He's also either killed all the other Reckoners cells or forced them into hiding.

Prof has hidden his own secret powers that the group hadn't known before and has gotten so much stronger with the powers we did know about. Prof is now more of a threat than Steelheart ever was! Now David will use his unique intellect and rally whats left of the Reckoners and forge new alliances and form a new plan. David forms a plan to unite with the man known as Knighthawk, the well known and neutral inventor/arms dealer who supplies both sides. Megan faces her own reality bending powers at David's encouragement and tries to master them to help the group on their final mission and David uncovers even more information about Epics and their powers/weaknesses.

With the help of Knighthawk, the Reckoners and Megan's evolved powers, David & friends find out about an alternate dimension with some minor and major differences and form a final plan to turn Prof after a few failed attempts. David finally uses his epic powers and discovers that the "appropriate" powers given to him were also ironic. He'd inherited the power profile of Steelheart!

Synopsis
When Calamity lit up the sky, the Epics were born. David's fate has been tied to their villainy ever since that historic night. Steelheart killed his father. Firefight stole his heart. And now Regalia has turned his closest ally into a dangerous enemy.

David knew Prof's secret, and kept it even when Prof struggled to control the effects of his Epic powers. But facing Obliteration in Babilar was too much. Once the Reckoners' leader, Prof has now embraced his Epic destiny. He's disappeared into those murky shadows of menace Epics are infamous for the world over, and everyone knows there's no turning back. . ..

But everyone is wrong. Redemption is possible for Epics—Megan proved it. They're not lost. Not completely. And David is just about crazy enough to face down the most powerful High Epic of all to get his friend back. Or die trying.