Thirteen-year-old Q and fifteen-year-old Angela know their lives will become complicated when his mother and her father, wildly popular musicians, marry, but soon the teens are involved with spies and terrorists in Philadelphia, Pennsylvania.

Nine-year-old Hannah, a Quaker living in Philadelphia just before the Civil War, longs to have some fashionable dresses like other girls but comes to appreciate her heritage and its plain dressing when her family saves the life of a runaway slave.

Frank and Joe travel to Philadelphia where they intend to prevent an attack on an extreme sports contest called the Big Air Games.

"When Cole moves in with his dad, Harp, he thinks life will be sweet--just him and his horse, Boo, hanging out with Philadelphia's urban cowboys. But when Harp says he has to get a job, Cole winds up as a stable hand for the polo team at George Washington Military Academy, where the players are rich, white, and stuck-up--all except Ruthie, the team's first and only girl, who's determined to show the others she can beat them at their own game. As Cole...

Lep, an apprentice to a doctor, helps his master take care of yellow fever victims in Philadelphia during the epidemic of 1793.

When a new Corpse leader, the Queen of the Dead, has taken command of the zombie invasion, Will Ritter and his friends renew their efforts to rescue Will's mother, prevent an assassination, and convince FBI Agent Ramirez of the truth.