Accidentally conceived, by the Consolidated Mechanical Men Corporation, Sprockets, the little robot, is something of a freak. From a special box reserved for special models, a malfunctioning mechanical tentacle had installed the genuine Asimov Positronic Brain in the robot's head, creating a mechanism with fantastic intellectual potential. Fearful of being dismantled, Sprockets escapes from the factory and finds safety in the home of Barnabas Bailey, renowned space scientist. Fortunately for man and robot, Sprockets becomes an amazingly useful ""instrument"" in Dr. Bailey's research. After a crash educational program in which Sprockets absorbs all the ""ologies"" and ""onomies"", Dr. Bailey, his son and Sprockets take off for the purple planet. The robot becomes a valuable interpreter in an encounter with Ilium and and a vital factor in the search for the quantic moonstones and in a dramatic rescue from the moon bats. The little group's adventures may seem routine to sophisticated members of the science fiction fraternity, but the sprightly personality and naive humor of this particular robot more than compensate.