Amy and Dan Cahill are no strangers to impossible tasks. After seven of their relatives were kidnapped, the siblings scoured Europe for the priceless artifacts Vesper One demanded in exchange for the hostages. But then the Cahill kids are given an assignment that pushes them to their breaking point, a journey to a legendary city. Amy and Dan know they can't afford to fail, yet they're running out of options and running out of time.

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.

Pat O'Toole has always idolized his older brother, Coop, right up until the day Coop ran away from their home just outside Washington, D.C. -- now a year later he has received a package containing a digital voice recorder and a cryptic message from his brother, which will lead Pat on a strange and dangerous journey to the mysterious Community living beneath the streets of New York.