Finn and Explorer Troop 301 face off against angry rock giants in the second book of this new chapter book series based on the award-winning kids' podcast!

Finn Caspian, his three best friends, and his robot Foggy are excited to explore a brand-new planet . . . until Finn's mom makes them bring along an annoying new robot named Voltronix Zu.

Putting up with Voltronix's bragging is bad enough, but when he accidentally turns the planet inside out, the Explorers get attacked by angry rock giants! Can the four friends find a way to save the planet--and the bubble aliens who live there--before Voltronix causes a volcanic disaster?

Blast off into a brand-new adventure inspired by the popular award-winning kids' podcast, now in its eighth season!