Steelheart is dead. Newcago is free at last. But the Epics still have the rest of the world in an iron grip. 
 Which means that the battle between Epics and Reckoners isn't even close to being over -- and David is headed to a new city, with a whole new crop of enemy Epics... plus one that is both familiar, and possibly not an enemy. "Firefight" does everything that a second book is supposed to do, with Brandon Sanderson adding a wider scope to the conflict, some shocking twists, and some revelations about the nature of Epics and their powers. 
 After a battle with an Epic, the Reckoners discover multicolored flower petals on her corpse. It's a sign that she was a minion of Regalia, a powerful water-manipulating Epic who rules the city of Babilar (formerly known as Manhattan), and that she's declaring war on the Reckoners. To further complicate matters, she is a former friend of Professor Phaedrus. Babilar turns out to be wildly different from the gleaming steel that David is used to -- a half-sunken city of strange indoor plants, glowing graffiti and underwater bunkers. 
 But after many years of relative peace, Regalia has summoned Obliteration -- a cruel fanatic who summons solar energy to obliterate entire cities. And none of the Reckoners have the faintest idea why. 
 To make matters even more complicated, David soon finds that Megan (aka Firefight) is secretly in Babilar. He still loves and believes in her, despite her betrayal -- but he can't convince his fellow Reckoners that she could be a good person. As time runs out for Babilar, David finds that the lines between friends and enemies have become blurred... even as he learns the terrible plan that Regalia has put in motion. 
 While "Steelheart" was a clever spin on the whole superhero/villain story, "Firefight" really makes the story of the Epics more... well, epic. The plot is no longer confined to Newcago, with Prof declaring early that "Instead of a single free city, we need to present to them an entire continent in rebellion." And Sanderson gives us glimpses of what has become of various cities -- some are destroyed, some are prisons... and some are colorful, ethereal places of glowing paint and nightly parties. 
 Part of what makes the Reckoners series so engaging is that Sanderson knows how to mingle the grim, apocalyptic setting with a quirky sense of humor, whether it's the bubbly Mizzy or David's endless weird similes ("You're like a potato! In a minefield"). His robust, fast-moving prose keeps the story moving along briskly even when nothing much is happening, and he weaves in some genuinely shocking twists (such as David's conflicts with the Reckoners, or his clash with Regalia). 
 At the same time, he comes up with some clever new revelations about the Epics, such as the nature of their individual weaknesses. It makes perfect logical sense, but isn't so immediately obvious that the characters seem stupid for not realizing it. And we get some interesting new Epics, such as the quirky, mysterious Dawnslight (two words: fortune cookies) and the crazy-fanatic Obliteration. 
 Now that he's no longer on a quest for vengeance, David has become the "heart" of the Reckoners. Sure, he may have killed multiple Epics, but he is slowly coming to realize that some of the Epics may be victims as much as those they hurt. And even as we learn more about Megan and her powers, we see her slowly being pulled back from the brink by David's purity and uncomplicated faith. At the same time, Prof is slowly slipping into darkness, because of the doubts that David is unwittingly giving him. 
 "Firefight" is one of those rare second volumes that actually amps up the plot and story from the first volume -- and leaves anyone who finishes it salivating for the third book of the trilogy. Brandon Sanderson, don't let me down.