Warcross is a science fiction novel by Marie Lu set in a near-future world where a virtual reality game has become immensely popular. The story follows Emika Chen, a skilled hacker and bounty hunter, who accidentally glitches herself into the opening game of the Warcross Championships. This unexpected event leads her to be recruited by the game's creator, Hideo Tanaka, to investigate a security breach. As Emika navigates the competitive world of Warcross, she uncovers dark secrets that threaten the game and its players. The novel explores themes of technology, identity, and the impact of virtual reality on society, blending action and intrigue throughout the narrative.