This book is about two girls named Catrina and Maya. Maya has a disease called Cystic Fibrosis. Cystic Fibrosis is a disease that affects breathing and digestion. Sadly there is no cure. That is the main reason Catrina and Maya`s parents have decided to move to Bahia De La Luna, California. Catrina does not want to go but she knows it is better for Maya`s health. Later on their neighbor, Carlos tells them that there are a lot of ghosts up at the mission in their town. Catrina does not like the idea of ghosts and gets sorta scared but, Maya is fine with it. Carlos then takes Maya and Catrina out for a ghost tour where Maya meets some ghosts and then Carlos gives her some kind of orange pop soda to make the ghosts come closer to her. But, then Maya drops the soda and the ghosts start swirling around her. Since Maya has Cystic Fibrosis she can`t handle it. Carlos and Catrina have to call 911. Catrina gets mad at Carlos for taking them on a ghost tour. As school starts Catrina starts to think that everyone in their town is obsessed with ghosts. Very soon it is Halloween Maya can not go because of the disease but, Catrina can. So Catrina meets up with her friends to do some trick or treating. After trick or treating there is a party for Dia De Los Muertos with the ghosts. At the party Catrina forgives Carlos, has a great time, and discovers who she truly is.