In the continued investigation of the ”Iraq War Syndrome,” David checks out a theory that the water purification system has malfunctioned. In Mexico, Jill and Carlos make a connection between a hybrid plant designed to detect land mines and the hemophilia epidemic. When that theory fails, David joins them in Mexico and explores the possibility that mosquitoes bred to eliminate malaria might be responsible. Bob quits NorBAC to pursue his love of perfume creation. Caroline receives the diagnosis she’s been waiting for.