Olivia's life is in turmoil ever since she accidentally froze all of the world's water and her aunt and uncle were kidnapped by the Wardenclyffe thugs. With the help of a black bear named Hoolie, she must travel across America to undo the damage she caused. Hungry and wounded, she stumbles into a secret valley invisible to the outside world. There she meets an ancient civilization with no intention of letting her leave. In the meantime, Doug and Gnat are drawn deeper into the world of Junonia, the mysterious city built in the aquifer beneath Florida. Doug works diligently to scientifically document the discovery of giant tardigrades when his secret is accidentally revealed to the last person in the world he wanted to tell, Larry Mutch. Caught in an epic battle, Doug must find a way to save himself, Gnat, and the bully who doesnt want his help.