An asteroid hits the Moon, causing fissures in its crust and sends a chunk hurtling toward Earth. Even worse is the threat that larger pieces will break off which could obliterate whole cities on impact. With the Moon out of sync, strange weather and huge tidal waves are threatening the population. Scientists conclude the only solution is to set nuclear charges on the Moon to implode it and keep it whole. The man for the job is demolitions expert, John Redding. Can he succeed in placing the charges correctly before an even larger piece threatens civilization?