An obscure medical researcher develops the "miracle enzyme" Bevvinase, thus enabling the direct conversion of carbon dioxide to oxygen within mammalian organisms, a major aid in the opening of Mars' hostile environment to permanent human residence. Decades later, a pair of deported, convicted felons, ex-intelligence officer and alpinist Jesperson, and his assigned work-partner, Barnes, are among several hundred carbon dioxide-breathing "Marsrats" dwelling in Burroughs Enclave, an enclosed, pressurized crater housing the denizens in the long shadow of the immense Olympus Mons shield volcano and its vast aqueduct system, the only available source of quintessential water on frigid, arid Mars. The enclave teeters on the brink of becoming a "lost colony" due to a major quake that causes unknown damage to the aqueduct system, and water flow stoppage. With time to avoid doomsday and uncontaminated water running out at a semi-equivalent rate, and home world help unavailable due to insufficient months for effecting a remote rescue, Jesperson and Barnes struggle against opposition from the residents' council and a derisive expert who believes climbing the volcano a total impossibility, and favors searching for deeply buried water ice. Jesperson and Barnes lead a last-resort, semi-suicidal trek up the six-kilometer-high escarpment, and onward to the rugged lower middle slopes of by far the largest volcano in the Solar System to effect repairs and assure the survival of Burroughs Enclave's denizens. About the Author: William Walling is a retired aerospace engineer who designed mechanical systems hardware at Lockheed Missiles & Space Company.