Series based on Raymond Briggs' bestselling children's book. In a vast underground construct called Bogeydom live the blissfully disgusting Bogeys, who spend their days wallowing in their own filth. Come night time, they venture 'up there', into the world of the humans, and, when these two worlds collide, everything filthy about the Bogeys is threatened by one impossibly wholesome family. Fungus is worried - he has been spotted by a human ('dry cleaner') on one of his trips up top.