Warcross by Marie Lu

When teenage coder Emika Chen hacks her way into the opening tournament of the Warcross Championships, she glitches herself into the game as well as a sinister plot with major consequences for the entire Warcross empire.
Booklist (July 2017 (Vol. 113, No. 21))
Grades 9-12. Lu takes a sharp turn out of the dark fantasy universe of The Young Elites (2014) and into the glittery, high-tech sci-fi world of a futuristic Tokyo. Emika Chen, hacker extraordinaire, has been scraping together a living on the streets of New York, working as a bounty hunter who tracks down people betting illegally on Warcross, an insanely popular virtual reality game. But it’s not enough to get by, and a desperate Emi hacks into a Warcross tournament game to scavenge. But she gets more than she bargained for when she’s invited to Tokyo by Hideo Tanaka, Warcross’ creator. There’s something insidious going on behind the scenes of the game, and Hideo needs the help of a hacker-spy. But the world Emi has entered is one of twists and double-crosses, and even her skills might not be enough. Despite some technological deus ex machina, this is an inventive first in a series that showcases Lu’s versatility as a storyteller. STEM tie-ins abound, and the thrilling plot turns will have readers happily strapping in for the ride. HIGH-DEMAND BACKSTORY: Dystopia, dark fantasy, and now a sci-fi thriller—what can’t Lu do? Her boatloads of fans can’t wait to find out.