Mattius the Martian Hunter and the Silver Box

What would you do if you were the son of the last great Martian Hunter? You'd save the world from the Martians that are robbing children of their souls, that's what. You probably wouldn't do it with a broken down dog, a faded comic book hero, a lumbering ex-con man-child, two intergalactic seniors and a mysterious silver box left to you by your deceased father. Then again, you're not Mattius.