BLACK HORIZON The most dangerous enemies are the unseen, and Mack Bolan's instincts are kicking in, alerting him to a horrific conspiracy so deep within the U.S. government that invisible spooks with unlimited power will never be held accountable for the atrocities they unleash. One conspiracy wrapped in another: an Armageddon group called Sons of Revelation, a man-made plague set to be released in south Florida, and rumors of terror imports from...