It's been a year since her older sister's murder, and Echo is still far from being completely alright. Echo has been trying her hardest to be the strong one, while her mother takes too many antidepressants and her father works too much. Now, at the start of her freshmen year of high school, Echo receives an unlikely gift from Zoe's old boyfriend: her diary. Echo is hesitant to read it but can't put it down after she gets caught up in Zoe's secret life.