How It All Goes Down
Nikki is a high school student who has just spent one hundred years in the Everneath as a Forfeit, getting sucked dry of all her emotions and memories. Cole, the Everliving immortal doing the sucking, seems surprised that she survived the Feed intact (a.k.a. still a teenager, and not crazy). He offers Nikki a place by his side as an immortal, but she refuses, and returns to the Surface even though she only has six months there before the Tunnels claim her as a human battery.
Nikki tries to make things right with her family, which is composed of her dad and brother. And when she goes to school, she hears rumors about how she disappeared because she was in rehab. Then she sees Jack, her boyfriend from before she'd disappeared. Things are awkward. She returned for him, because keeping his face in her mind helped her survive the Feed, but now she has no idea what to say to him. Ugh.
Cole shows up and starts bugging Nikki, saying he still wants her to choose eternal life with him rather than suffering through six months on the Surface followed by an eternity in the Tunnels.
As these events unfold, we see through flashbacks how Nikki and Jack got together. They were childhood friends and eventually started going out. He's a football player who's dated around, so she feels super inadequate. She's also depressed because her mom died in a car accident with a drunk driver, and that dude is currently on trial. Nikki gets to know Cole, the hot lead singer of the band the Dead Elvises, and when she gets hurt in a rafting accident, Cole takes away her pain.
Then Nikki catches Jack with an ex-girlfriend in his room at football camp. Between this and the fact that the guy who killed her mom has just been cleared, Nikki wants to get rid of her pain. So she goes to Cole, who begins to feed off her emotions and prepare her to go underground with him. When she leaves, she doesn't say goodbye to her family or Jack.
So Nikki's working through her reasons for vanishing with Cole while trying to get her life back. Her dad makes her volunteer at a soup kitchen, where she meets a crazy old lady named Mary who seems to know her somehow. She decides to help Mary by trying to figure out what she's looking for.
Nikki also figures out that Cole is trying to get her to push Jack away, so she chooses to tell Jack everything, even though it seems far-fetched. Together, Nikki and Jack learn that Mary is Meredith, a girl from their school around their age. One of Cole's band members fed on Meredith, though, causing her to age and lose her sanity. Yikes.
Nikki can't bear to hurt Jack again, so she doesn't tell him that the Tunnels are coming to claim her soon. Cole, who's been stalking Nikki using another person's appearance (hey there, Neal), spills the beans in an effort to drive Nikki and Jack apart. Jack leaves town, and Nikki freaks out, thinking that he has actually left her.
With days to go before the Tunnels take Nikki away forever, Jack comes back with Mary. The Tunnels take Mary, but not before she gives them a clue, related to the bracelet that's been in her family (the Daughters of Persephone). With a little help, Jack and Nikki figure out that the bracelet contains a key to harming an Everlasting. They try to destroy Cole's guitar, figuring it houses his heart, but they are wrong. The Tunnels come, but Jack puts together some of Mary's clues and takes Nikki's place in the Tunnels.
Jack is gone. Nikki gets to stay in this world. She dreams of Jack every night, and knows that their contact sustains him, keeping the Tunnels from draining him completely. She will find him.