The USA TODAY bestselling novel of terror from "one of the hottest horror authors on the planet" ( Paste ) and writer of the #HorrorBookTok sensation The Troop follows five elderly volunteers in an aging-reversal experiment where an ancient biological agent unleashes a terrifying fight for survival! On a remote island in the Canadian wilderness, five elderly volunteers from different walks of life are given a tantalizing offer: join a radical experiment designed to stall their biological clocks or even reverse them, restoring their lost youth. The chance to put death on pause--forever, perhaps. The remarkable secret lies in the high-tech harnessing of an ancient and extraordinary biological agent.one with no conscience, yet possessed with a single-minded purpose that has helped it persist for eons: the will to survive. The dark heart of unbridled human ambition finds its apex in an unholy act of human experimentation, turning the quest for immortality into a horrifying fight for survival that tests the limits of both creator and subject, eclipsing all bounds of morality and sanity.