Colonel Boyd has worked most all his life at making the frontier of Mars more habitable for humans. He's fought the mutant natives, survived deadly thunderstorms, and lived off the strange and often inhospitable land outside of the safety of the clan cities.

When the entire population of the Enginetown settlement goes missing, Boyd commissions a tracker, Doherty, to help him find the lost folk. Boyd knows Doherty to be his son, but has never met him before. As the two are drawn toward a violent confrontation with a pack of natives, Boyd also confronts the path of fatherhood he never approached. Regret swells within Boyd, and he must decide whether his long and often bloody treks in the frontier have transformed him into something even less human than the mutants he's spent a lifetime fighting.