Gemma is an eighteen-year-old girl living in a small town called Afton with her grandparents Sophia and Marco—the most unaffectionate and distant people ever. Gemma used to not feel emotions at all, but recently she's been bombarded with them, and on top of that, she's had these scary nightmares about ice demons chasing her through the woods. Yikes.
She goes off to school and sees a cute new boy named Alex who's just started at school with his sister, Aislin. Gemma feels odd sparks of electricity whenever they talk and touch, but Alex seems to completely hate her.
Alex, Aislin, and Gemma have to work together on an astronomy project. One day, Alex takes Gemma to the woods and shows her a spot where a star supposedly fell two decades ago; he says that a group was sent to protect the star. Okay…
Later Alex comes to Gemma's house and she overhears him talking to Sophia as though they know each other. One night, they all go on an astronomy field trip and when Gemma looks into the telescope, she sees a vision of a woman talking to a little girl. This freaks her out and she runs to the school bus. Alex follows her and they kiss right before the ice demons from Gemma's nightmares show up for real. Before the ice demons can freeze them to death, Aislin bursts in and does something with a crystal—and Gemma feels herself being sucked into a dark tunnel.
When Gemma lands, she learns that they are in a house outside of Las Vegas and that Aislin transported them there via magic. Alex explains that he and Aislin are Keepers, which means they're part of the group sent to protect the star because the star is the only thing that can prevent a portal from opening and letting out a bunch of Death Walkers (those scary demons) that will end the world.
He also reveals that Gemma has the star's power inside of her because her mother, Jocelyn, was a Keeper, too, and hid the power inside her baby. Whoa. Aislin returns with the owner of the house, Laylen, who is a vampire.
They decide to go into town to get Aislin another crystal so that she and Alex can go back to Afton and look for Marco, Sophia, and Stephan—their father who is the leader of the Keepers. They need to find out from these folks what the heck to do next.
When they drive into Las Vegas, Laylen has them stop at a vampire club first so that they can steal the Sword of Immortality, which is the only thing that can kill Death Walkers. At the club, they are attacked by a couple Death Walkers, though Alex is able to kill them with the sword. Phew.
Then they go to a store where Aislin picks out a crystal. While there, Gemma accidentally touches a crystal ball and is sucked into a vision where she sees the same woman and girl from before—except now there is a man forcing the woman into a lake. She cannot see their faces fully, but the vision disturbs her even after it ends.
Alex and Aislin go to Afton to look for everyone else while Laylen remains behind with Gemma. He tells her that Stephan is very power hungry and might have been involved in her mother's disappearance. This little truth bomb shocks Gemma, and then Death Walkers attack and Gemma stabs one before Alex shows up to save the day. Again.
Alex has Aislin transport him and Gemma to a cabin where they can stay safe. After they arrive, they go to the grocery store to pick up some supplies and a guy named Nicholas starts chatting Gemma up. Alex pulls her away and they go back to the cabin, but when Gemma walks in, the Nicholas guy is there and says that he's taking her with him. Um… no? He tells Alex that because Gemma saw a vision, she belongs with the Foreseers according to the rules of the magical world.
Nicholas takes both of them to the City of Crystal, where the Foreseers live. They meet with Dyvinius, the leader of the Foreseers, who says that the Keepers can have Gemma for the time being, but she will eventually have to come complete her training to be a Foreseer.
Then he tells her that she has to "fix" the vision she had before she goes back with Alex. Say what? Basically, because the faces in the vision were blurry, Gemma has to go back in and make sure they become clear. When she does, she learns that the woman is her mother, the little girl is her, and the man who forces her mother into the lake is the same one who is in her dreams. He has a distinct scar on his face. Eek.
They return to the cabin and Alex reveals to Gemma that the reason she doesn't feel emotions is because they detached her soul from its feelings—and Stephan wants to take away her soul completely, because if she is emotional, the star's power drains and may not work anymore.
Understandably, Gemma gets pretty upset so Alex gives her a locket that her mother gave to her before kissing her again. When Gemma opens the locket up to see the picture inside, she realizes that Stephan is the man from her dreams and the one who pushed her mother into the lake. She is upset and tells Alex that he can't trust his father, which makes him angry.
Then Stephan shows up with all the Death Walkers and Gemma goes running off into the woods. Stephan finds her, though, and stabs her in the leg to teach her a lesson. Then he brings her back to the cabin, where he opens a box with a stone inside. He says that it will both remove her soul and completely wipe her mind so that she won't even be able to function anymore. Gemma is horrified and looks to Alex, who does not help her. Slowly, her eyes close and she feels nothing.