"Most kids are nervous about their High School Graduation. But most kids don't have to testify in court, defeat a demon, and save the world on the same day." Now that his mother, Susan, has been charged with attempted genocide, Kalib is the key witness for the prosecution at her trial. But when a supernatural plague is unleashed on the citizens of Hainesville, causing dangerous mass hallucinations, Susan seizes the opportunity to blame her accusers and turn the infected townsfolk violently against Kalib and his friends. Now, Kalib races against time to find the fabled city, rumored to contain the secret to stopping the plague. But will he be able to unlock the mystery, rescue his friends, and discover the traitor in his camp before it is too late? The third book of the award-winning series, The Invisible City, is a rollercoaster of danger, intrigue, and betrayal.