Warcross by Marie Lu summary

     Emika is living in NYC struggling to make ends meet after the death of her father.  She becomes a bounty hunter to try to pay the bills and the book starts with her going after a high value bounty. 
     The bounties she takes on are for the police who are searching for disreputable characters in Warcross, a virtual reality which has taken the world by storm (think the OASIS from Ready Player One). 
     She catches her bounty but another bounty hunter called it in that they had caught them first so even though she is the one that turns the bounty over she doesn't get the reward money. 
     Since she and her roommate are about to be evicted from their apartment for nonpayment she becomes desperate and hacks into the opening ceremony of the Warcross championship, which is like the Olympics where the best of the best at Warcross compete for cash and prizes.
     She hacks in to try to steal some powerups from the players, which are shown as marble looking items that assist with speed and other advantages in the competitions and some are worth a lot of money so that's why she is trying to steal them.
     In the process of the hack, she is glitched into the game and can be seen by all the spectators.  She immediately logs out but her face is on the news within hours and she awakes the next day to a phone call from none other than the creator of Warcross himself, Hideo Tanaka. 
     He tells her that her debts have been taken care of and he wants her to come to Tokyo to meet with him.  She of course agrees since he is her idol and she has looked up to him since she was a little kid.
     Upon arriving in Tokyo he tells her that he has a job for her.  She will be entered as a wildcard in the Warcross championship to help him find another hacker who is messing with the Warcross system. Each of the teams in Warcross selects wildcards from the player base each year so this isn't unusual and she'll be able to go in incognito.
     He chooses her because only one other person has been able to hack into the Warcross games which is this unknown entity named Zero and so that's why he feels that someone of her caliber will be able to catch them.  Her reward will be 10 million dollars if she succeeds, but he tells her that he has also hired other hackers too so it is a competition in itself to try to see who can catch Zero first.
     Emika is picked by the Phoenix Riders to be their wildcard and she is first wildcard pick which starts even more tabloid fodder about her even though we find out later on that Hideo didn't even set that part up.  Asher (the Phoenix Riders captain) chose her on his own since he realized how great her hacking skills must be with glitching into the tournament.
     While hacking into her team and other teams personal files to try to find clues about Zero (Hideo thinks Zero is another Warcross player), Emika discovers that the other wildcard on her team named DJ Ren has many firewalls on his info where the others don't so she begins to tail him, suspecting he is Zero. 
     During this time, she has meetings with Hideo regarding finding the hacker and they begin to fall in love based on their shared life experiences.  His brother was abducted when they were young while they were at a park playing, and she shares with him her father's gambling addiction and death and her mother's abandonment.
     At one of their meetings, Hideo gives Emika a hack which can get past Ren's data encryption if she can get close enough and she uses it on him in the tournament while they are playing and manages to grab a file that is called "proj_ice_HT" which she figures out means "Ice Hideo" aka assassinate Hideo.  She turns the info in to Hideo and even though an assassination attempt is made on his life at one of the events he tells her to continue tracking Ren and they will act like Ren isn't a suspect for now in order to glean more info. 
     Emika follows Ren into the Darkcross (an underground of Warcross with illegal betting and powerup trades along with other illegal things like virtual prostitution) one day to try to find out more about what he's doing. 
     She sees him betting on a Darkcross game and another entity shows up in head to toe black armor and she realizes it is Zero. 
     Ren and Zero begin placing strange betting numbers on the game and she figures out it's a code and begins recording the numbers. 
     Later on in her room she finds that the numbers are coordinates around the world at some of the biggest cities and she sees that Zero has much more influence and is planning something even bigger than she thought for the Warcross finale.
     At one of the last games of the tournament in an underwater level Zero glitches himself and Emika into a cave away from the eyes of the other players and spectators and offers her an alliance, saying that if she'll help him he can pay her more than Hideo but she of course refuses. 
     He once again shows up at the Warcross championship apartment she shares with her team and asks her to reconsider and when she refuses he steals the memories she had of her father that were stored in her files and then he blows up the aparment building. 
     She and her teammates make it out, but Hideo tells her that he's pulling her from the tournament since it's become so dangerous and he can't lose her.  He also has Ren arrested for questioning and pulls him from the tournament as well.
     Emika knows that whatever Zero has planned is huge and she can't let it go so even though she promises Hideo that she'll stay out of the investigation, she tells her teammates everything and they agree to help her catch Zero. 
     One of the other players in the game, Tremaine, reveals to Emika that he is another of the bounty hunters searching for Zero and he gives her the info he had collected which includes another piece of the proj_ice encryption which she then is able to decrypt and sees that it is a plan to install a virus in Warcross through the artifacts in the final game.
     She once again goes into the black market and with the money Hideo has given her buys several illegal powerups to use in the final game. 
     When the game starts she takes over the new wildcard on her team's account and goes into the game as him.  She finds out that Zero has glitched into the game by the same means and is controlling the account of the opposing team's captain.  She manages to steal the artifact from him and deactivates it and the artifact from their team too, preventing Zero from installing the virus.  He tells her that "she triggered it" and she tells him that she has stopped him and he needs to give up at which time he tells her that all he is trying to do is STOP Hideo and then he disappears.
     She confronts Hideo about it and he reveals to her that he has upgraded the neurolinks used for Warcross so that now instead of just receiving data and letting the users control the link to their mind, he can now use that same link to control them instead and he is planning on using it to stop any crimes and she has helped him activate it since she didn't stop Zero. 
     He shows her a current happening where a man is planning on robbing a convenience store.  The neurolink kicks in and his brain is "rewired" so that he puts the gun away and leaves, forgetting what he was planning on doing.  Hideo explains to Emika that this will stop all crime in the world (this has been his plan all along because of what happened to his brother and the guilt he feels about it) and he asks her to understand and help him and even though she sees the good it could do she also sees that it takes away free will and it breaks her heart to do it but she tells him he will have to do this on his own and she can't be a part of it.
     Emika goes back to the Warcross apartment to meet up with her team and explains everything to them.  She realizes that with one of her hacks she has still been gathering info on the Warcross players while in the game which means that she has some of Zero's files now.  She begins going through them and finds that Zero is actually Hideo's brother, Sasuke.
     Emika wonders why Sasuke hasn't come forward in all these years.  Is he being controlled by someone else to act against his brother?  Does he even know who he is anymore?  Is it even Sasuke or is this just another deceit?  Around this time she gets a message from Zero which says "My offer to you still stands" and all her filed memories of her father are returned to her.
     Emika wonders who she should actually be helping; Zero, who tried to stop Hideo but used such violence in the process, or Hideo, who she really loves but doesn't want to endorse because his plan takes away free will.
     The book ends with Tremaine coming outside to tell her that another bounty hunter contacted him and that he thinks this hunter can help them with finding Zero and Emika agrees to go with him to find the bounty hunter while still being unsure on who she should actually be trying to stop.