When a Congressman, a lobbyist and a Capitol police officer are stricken with a mysterious disease, Dr. Connor and his NIH team fear a terrorist plot, until the leader of a prostitution ring becomes the fourth victim. An uncovered list of "clients" turns up a "Who's Who" list of leading Washington figures, forcing the team to walk a fine line between politics and protocol to contain what seems to be a deadly STD. Meanwhile NIH Director, Dr. Ewing and Eva fight to keep the story out of the headlines. As the death toll increases and a blood test yields unexpected results, Connor's team must search for clues in the unlikeliest of places.