Alex is the protagonist of the novel. She grew up Los Angeles, California. Her grandmother is Jewish Ladino and her father is Hispanic. As a child, she was plump, but as an adult, Alex is thin and wiry, with long black hair and tattoos covering her arms. She has the ability to see Greys, or ghosts, which causes her terrible problems as a child and teenager. Alex has no friends and is bullied at school. Eventually, she discovers that taking drugs dulls her supernatural affinity, and spirals into addiction. When her mother Mira tries to force 15-year-old Alex into a rehab center, Alex runs away from home.

Alex moves in with Len, her drug dealer and boyfriend. Len expects her to sell and deliver drugs and to prostitute herself for his benefit. There is no indication in the text that Alex loves or even likes Len, but she has no other place to go to and being homeless is not an option. Most of Alex’s feelings revolve around her best friend Hellie; their physical closeness hints at romantic desire.

After Alex takes deadly supernatural revenge for Hellie’s rape and death, Yale’s Lethe society recruits her to become its new Dante—a freshman who apprentices to becomes the head of supernatural policing on campus.