[downer]

If you want the players to hook up with the "Wizard" you could hint that the Martians used to know a way to travel to other planets, and have the Wizard offer to take them back as payment for their services. Maybe the fellow turns out to be a bad egg himself in the end, who wants to develop a similar weapon to the one that brought the characters to Mars. Thus creating the interesting dilemma of whether the characters let him continue, so they can return home, abandoning the Martians to his tyranny, or stop him, losing their way home in the process.