Problems arise for Amelia when she starts sixth grade at the same middle school where her older sister Cleo is an eighth-grader, and she gets the school's meanest teacher for three of her classes.

Ten-year-old Amelia watches her older sister Cleo change when she gets her first boyfriend, while Amelia takes a class in "life skills" and tries to figure out what it means that she likes shop class better than home economics.

To rescue her missing mother, thirteen-year-old Mira must travel to sixteenth-century Rome, where she befriends the painter Caravaggio and other artists and scientists under suspicion for being forward thinking individuals.