Jilly’s sixteenth birthday takes a deadly turn when vampires come out of hiding and take over New York City. Blood-sucking birds fly over the sky, hunting for anyone who has not found shelter. When the bloody conquest began, she was waiting outside a club for her best friend, Eli, and his boyfriend, Sean. Although Jilly used to be in a relationship with Eli and still loves him, he fell out of love with her and in love with Sean right after they met. Meanwhile, Jilly’s relationship with Sean is strained, and the two only put up with each other for Eli’s sake. After escaping from the club and returning home, both of Jilly’s parents are killed three days after her birthday. All the internet and cellular service is down, but Jilly is able to safely reach Eli’s house to check on him. To her relief, his entire family is okay, and they still have food. The two friends have a warm and tearful reunion, and Eli reveals to Jilly that he wants to go looking for Sean. She is against the idea, but he goes against her advice and she reluctantly follows. They head to their high school and find that there are thousands of humans seeking refuge there. One of the teachers tricks Jilly and locks her in a classroom with Sean, who has turned into a vampire. He offers her a choice between who he will turn into a vampire: her or Eli. The other one will be used a blood source, and Eli will be offered the same choice. She chooses to sacrifice herself in order to save Eli, and Sean says that Eli chose the same thing. Eli surprises them both by staking Sean in the heart just before he is bitten. He kisses her and then kisses and mourns over Sean’s dead body. He starts saying that Sean truly loved Jilly, but she realizes that that explanation is just his coping mechanism. Jilly accepts that she and Eli love each other in their own ways. Eli finally wishes her a belated happy birthday, and his phone suddenly gets a notification, signaling there may be hope for the future.