Having rescued her town from zombifying mutant mushrooms, eleven-year-old Magnolia Stone is ready for her next adventure! Maggie and her best friend, Nate, head to Yellowstone National Park to visit Maggie's park ranger dad. But when the kids bump into a rogue Komodo dragon, a dangerous predator that shouldn't even be in the park, and a major earthquake leaves Maggie and Nate stranded, they set off to figure out what's going on and to reunite Maggie's family once again.

While Maggie comes up with scientific solutions as they battle earthquakes, landslides, wolves, and other unusual creatures, Nate focuses on conspiracy theories and getting stellar footage for his YouTube channel. But only by combining their skills will they have any hope of saving Yellowstone or each other.