Although most people may not notice this, the living world is rife with an everpresent, invisible chemical conspiracy: pheromones. These chemicals can warn of danger, entice mates, mark territory and produce sophisticated behavioral changes in every species they touch -- but what about humans? Conventional science has argued humans don't play the pheromone game, but as Ben, Matt and Noel learn in tonight's episode... there may be more to the story.