Deep inside Mexican cartel country, a dirty bomb is making its way north across the U.S. border. The location and eventual destination remain uncertain, but Mack Bolan is closing in on the radioactive caravan with luck and some dubious associates as his only allies. Bolan's orders are to find and take out the immediate threat, but he soon discovers that his mission doesn't end there--it's just the beginning of a bigger, grimmer picture that involves...