The series depicts a post-apocalyptic world in which the appearance of an orbiting cosmic phenomenon known as Calamity has given random people superhuman powers in apparent defiance of known physical laws, turning them into "Epics".

Twelve years ago, an object dubbed Calamity appeared near Earth and burst in the sky, emitting a strange radiation which gave a small group of humans superpowers and near invincibility in apparent defiance of the known laws of physics.

He tracks "the Reckoners", an elite group led by "Professor" Jonathan Phaedrus with the common goal of killing as many Epics as possible.

Yet Steelheart has proved one of the more effective Epic rulers, by providing Newcago with infrastructure, food, water, and electricity, in contrast with most other cities in what are now known as the "Fractured States".

The United States, and other parts of the world, were changed forever when a glowing red light in the sky known as Calamity gave normal people superhuman powers and abilities.

During this time, David's father grabbed one of the dead guards' guns and prepared himself to kill Deathpoint, believing that Steelheart was a hero.

This also saved him because Steelheart came back with another Epic named Faultline and sank the entire building into the ground, killing all of the other survivors and the rescue workers.

Among this group are the leader and founder of the Reckoners, Jonathan Phaedrus, who is called Prof throughout the book, Tia, Abraham, Cody, and the newest recruit, Megan.

They also have a machine called the Harmsway, which is used to quickly heal wounds, and they have clothing that projects a small and fairly effective protective force field.

David is able to kill Nightwielder, but Firefight turns out to be Megan, who is revealed as an illusionist Epic with reincarnation abilities who had infiltrated the Reckoners.

[1] After the events of Steelheart and Mitosis, David Charleston, dubbed as the infamous 'Steelslayer' by many, is searching for something to fill the hole left now that his revenge had at long last been fulfilled.

Upon arriving in Babilar, a ruined NYC flooded up to the top of the skyscrapers, which are used by the citizens as homes, connected by ladders, Prof, David, and Tia meet with Val, the tough-headed operations leader of the Babilar Reckoners, Exel, the extremely large and friendly giant of the team, and Mizzy, the spunky and clumsy point/repair and equipment manager.

Suddenly, nearby rooftops blaze and explode, and it's revealed that Regalia has brought in Obliteration, an incredibly strong and cryptic Epic who has a flair for the theatrics and is famous for desolating Houston, San Diego, and Albuquerque, not wanting to rule, but simply to destroy.

With the abilities to absorb and disperse amazing amounts of heat, teleport in the wake of danger, as well as enhanced strength, he runs rampant throughout the city, killing citizens seemingly joyously while the Reckoners try to exploit a weakness.

The lopsided scuffle ends with David being thrown into the depths with a ball and chain, before Obliteration graciously thanks him for slaying Steelheart, saying it's simply an obstacle averted in his quest to destroy everything in his path.

David, who is obviously uneasy about water, sees Prof return, and implores that perhaps Regalia is trying to resist the Epic powers, to which Tia agrees.

Exel and Mizzy help David learn to use the spyril, a piece of Knighthawk machinery that allows the user to use it as a jet pack of water.

After plenty of training on this, David and Mizzy are sent to a Babilar party to spy on Newton, a gang leader in the city and an Epic working for Regalia.

Megan, who is trying to resist her Epic temptations, tells him that she finds it easier to control herself around him, and the two have a laugh in the wake of a bad metaphor by David.

Megan gives David a motivator, which is a small object that helps Knighthawk technology work, before leaving him, threatening him with a gun when he tries to kiss her.

The two discuss the morals of Reckoners and Epics, and while David tries to figure out her location by triangulation, she states that he has only hurt society by killing Steelheart, and that he will be the end of his own people.

However, the conversation is cut short when it's discovered that Obliteration is sitting on top of a rooftop in Babilar, collecting up heat from the sun, most likely in an effort to vaporize the city.

David keeps in touch with Megan via text, and Prof (who is thinking of a plan to stop Obliteration from destroying the city) becomes suspicious that he's putting her in front of the mission to end Regalia's reign over Babilar, and even threatens to send him back to Newcago.

While going out with the others to scout Obliteration's spot, David goes into the interior of a building and notices odd fortune cookies hanging off of vines from the large vegetation, with notes inside asking for help, saying that "She has me captive".

The group sets up around Obliteration to spy on him, when Newton is noticed nearby, as well as Knoxx, another Epic thug who can change into a pigeon (among other animals, it is later revealed).

Megan reveals that she is not, in fact, an illusion-making Epic, but can pull semi-real objects and people from alternate universes, and her weakness was fire.

David is too late, but discovers that Megan had rigged the high-tech gun Tia gave him to shoot her future self should she die of fire, which was her weakness and would disable her reincarnation abilities, and had succeeded.

Ildithia is known for its abundant produce, due to an epic named Stormwind whose presence provides rain and unnaturally fast crop growth near the city.

Prof, agonized by her death, destroys the entire Sharp Tower, and Megan manifests a parachute to barely allow them to survive the fall.

David, armed with an Obliteration-powered bomb, is deposited at Calamity's red star (actually the International Space Station, which has been turned to glass).