It started with a kidnapping. A shadowy organization known only as the Vespers snatched seven members of the Cahill family and demanded a series of bizarre ransoms from around the world. Thirteen-year-old Dan Cahill and his older sister Amy began a global treasure hunt, determined to bring back whatever Vesper One needed, so long as it kept the hostages safe. But when they deliver the last ransom, Amy and Dan discover Vesper One's terrifying endgame....

For many long years, Atlee Pine was tormented by uncertainty after her twin sister, Mercy, was abducted at the age of six and never seen again. Now, just as Atlee is pressured to end her investigation into Mercy's disappearance, she finally gets her most promising breakthrough yet: the identity of her sister's kidnapper, Ito Vincenzo. With time running out, Atlee and her assistant Carol Blum race to Vincenzo's last known location in Trenton, New Jersey...