The planet Rhydin is a fairly large bluish sphere, a somewhat atypical M-class world. Orbiting it, beyond a ring of cosmic debris and man-made satellites, are two moons. The larger and closest of the two, Arabrab, follows a slow and steady path across the Rhydin skies. The smaller and more distant moon, Trebor, loops around the planet in a speedier (but far more elliptical) orbit.