When a newspaper reporter is killed by a letter-bomb, Don and his team believe it's the work of a suspected serial bomber who a few years ago eluded a conviction for letter-bomb attacks on bio-tech labs after his student took the fall. After analyzing the suspected serial bomber's background, Charlie realizes he has a lot in common with the man intellectually and questions whether they've got the wrong guy. While Don thinks Charlie's emotions are clouding his judgment, Charlie ultimately proves the suspected bomber is being framed and it's only a matter of time before the real bomber strikes again.
