The Starmen's search for the Benefactors leads them back to Mars. They must find the Benefactors before the vicious Xenobots destroy Earth in their search to destroy their 'ancient enemy'. But on Mars, people are strangely uncooperative, even though the same Starmen had been instrumental in saving Mars from Lurton Zimbardo's pirates. What the Starmen don't know is that the top organized crime boss on Mars has his own agenda, and he won't let the Starmen interfere with it.