Teenager Eliza and her friends are going to explore a cave near their upstate New York home, but first her friends insist on dragging her to Drowner's Swamp, a bog legendary for its dangerous sinkholes, and a place which her mother has frequently warned her about; Eliza does not want to go, and when the earth opens up and swallows her she finds herself in a system of caves--and what she finds living there is strange and dangerous beyond anything the...

14-year-old Will Burrows has little in common with his strange, dysfunctional family. In fact, the only bond he shares with his eccentric father is a passion for archaeological excavation. So when his dad mysteriously vanishes, Will is compelled to dig up the truth behind his disappearance. He unearths the unbelievable: a subterranean society that time forgot. "The Colony" has existed unchanged for a century, but it's no benign time capsule of a bygone...

The outer crust is under attack by the subterranean Styx who are turning ordinary humans into walking bombs and incubators for their eggs, and only Will Burrows and his band of retired commandos stand in their way--but the Styx also have problems of their own.

Determined to prove her conspiracy theorist father's beliefs about lost Cold War technology, Gillian, her skeptical brother, and their friends journey to the ruins of a vast doomsday bunker before they are confronted by dangerous adversaries.