Twins Fox and Fibber are riding on a train through Germany when it plunges into a dark tunnel--and emerges in Jungledrop, one of the Unmapped Kingdoms in charge of controlling the weather in their world. The land is beautiful but perilous, with grizzlebears and gobblequick trees. Together, they must brave the glow-in-the-dark rainforests to find the Forever Fern. Along the way, they learn to work together, see the beauty in the environment around them, and forgive themselves for past mistakes.