Zach Lightman’s father died when Zach was one. Zach has been consumed with the desire to know his father for as long as he can remember. His only other remaining family is his mother, who is a nurse. She has never remarried.

The other people in Zach’s lives are his two best friends both named Mike, whom he calls by their last name Cruz and Diehl. He also has an ex-girlfriend he can’t forget about, not to mention an arch-nemesis who threats to be his undoing. Zach works at the Starbase Ace, which is a used video game store. His boss and owner of the store, Ray, acts as his surrogate father.

Zach’s life consists of playing video games, obsessing about his father, pining after his ex-girlfriend, hating his nemesis, loving his mother, and working at Starbase Ace. He is two months away from graduating high school. Despite his mother and Ray’s concern, Zach’s only post-high school plan is to work full-time at Starbase Ace.

Everything changes one day when he spots a spaceship from his classroom window. It’s not just any spaceship. It is the spaceship from the video game he plays. At first, he questions his sanity because no one else seems to have seen it and there are no news reports of alien space ships. However, the next day when he gets to school, a spaceship lands on his school’s lawn. This is not the alien spaceship he saw the day before, but the government spaceship from his video game. Ray walks out of the spaceship looking for Zach. Zach is taken on to the spaceship in front of the whole school and the spaceship flies away.

On the spaceship Ray explains some things to Zach. The government has been preparing for an alien attack. Video games were made to train civilians without causing panic. It was also a way to recruit top talent. Zach has been recruited because he ranks in the top 10 of the video game that is a simulation of the alien attack. This is the reason he actually saw an alien space ship that looked like the space ship from his video game and why he was sitting in a government space ship that looked like it was from the video game. Ray was actually stationed in Beaverton, OR to train and keep an eye on Zach. Zach wants to know about his father but Ray does not have information about that.

Once at the base, which is in Nebraska, he is taken to a large briefing room where all the new recruits were brought. He immediately sees and falls in love with a woman with tattoos. Her name is Alexis, nickname Lex. He sits next to her and they become friends. In the briefing they are told that the government has known about the alien attacks for more than forty years and now they are down to 10 hours before there will be a three-tiered attack that is meant to obliterate the world. There are details about the briefing that leaves Zach unsatisfied. For example, why have the aliens taken 40 years to attack, giving humanity an opportunity to technologically catch-up if they could have eliminated the earth back then? However, nobody seems to think this is worth thinking about.

During the briefing, the base is attacked and the new recruits must immediately go into combat. They fight with drones, controlled remotely. Zach disobeys orders and causes the destruction of a fleet of drones. When he is called into the admiral’s office he expects to be court martialed. However, he is only mildly reprimanded. He is then told that his father, Xavier Lightman, is alive. Xavier was recruited seventeen years ago and the government staged his death so he could work in the service. He’s been stationed on Moon Base Alpha (MBA) where Zach is also being sent.

Zach meets the other top recruits on the spaceship traveling to MBA. There are five of them there. Zach is ranked five and the others come right after him. When he gets off at MBA, his father is there to meet him. They have only a few hours before it’s time for combat. His father gives him a flashdrive with every letter he’s written to Zach the last seventeen years. There are also videos of his father talking to him. The first video he sees, his father says that there is something he needs to tell him in person.

When Zach seeks him out, he finds out that his father also has the same question as he does about the alien’s motive. However, because he’s had seventeen years to think about it, he also thinks he’s figure it out. His father believes that, like the popular science fiction trope, the aliens are testing them. If humanity uses their secret weapon on the aliens, they will be immediately obliterated. However, if they voluntarily destroy the weapon themselves, they will pass the test and survive. He has been unsuccessful in getting the authorities to listen to him.

Zach does not know whether to believe his father or not. The time for combat comes with Zach still doubting his father. However, once they are in combat, Xavier risks his life to pass to first “test.” When Zach sees this, he decides that his father is right. Xavier is injured and Zach saves him. There is a reprieve of a few hours between the first and second round of attacks. Zach uses this time to take his dad home to his mom, rally his friends (old and new), and comes up with a plan.

The plan is for Zach to destroy the secret weapon controlling the drones his dad set out in space, his friends to protect him from the alien attacks of Starbase Ace where Zach is physically controlling the drone, and his father to physically distract the pilots that are controlling the drones that are escorting the secret weapon so Zach can destroy it. The plan works, humanity passes the test, and Zach is a hero. Unfortunately, Xavier is killed in battle.

It turns out humanity was fighting only itself. There is no intelligent life on Europa, only a computer placed there to be an Emissary of a peaceful intergalactic community called Solarity that wanted to test humanity. When Zach passed the test, the Emissary offered humanity membership to the community. Zach accepted on humanity’s behalf. The benefits that came with membership were knowledge about medicine and technology that greatly improved quality of life on earth. However, Zach is suspicious of Solarity’s motives. He doesn’t trust an entity that killed his father and millions of innocent people just for a “test.”

His father’s brief homecoming visit resulted in the conception of Zach’s baby brother J.R. Zach’s relationship with Lex also blossomed and she moved to Beaverton to be with him. Thinking of these people that he loves, Zach realizes that he cannot just sit on the sidelines and let things happen. He accepts the ambassadorial role offered to him in relation to Solarity. He hopes that by figuring out the real motive of Solarity, he will be able to protect those he loves and humanity in general.