Chapter Four: To Save Earth

From Ming's palace, Dr. Zarkov uses an astral projector to warn Flash in Arboria of the impending collision danger to earth and of Ming's planned metalmen's attack on Arboria. Even as Prince Barin's forest fighters rout the metalmen, Arboria is attacked on a second front by the molemen who burrow their way into the tree kingdom. Barin's men defeat this underground challenge and Flash and his friends commandeer the molemen's giant mole machine for a last ditch effort to save earth. Churning through molten lava, Flash guides the whirling mole machine into Ming's palace where he successfully wrests the planetary drive controls from Ming and guides Mongo away from earth. The chapter concludes as Flash and his friends on Mongo speed away from earth into unknown regions of outer space.