Balgo Ywain Parks is certain that his cute dog Osushi-chan is the perfect bait to get closer to Noel "Niiha" Niihashi, the object of his desires. Unfortunately for him, Noel is used to dealing with creatures far worse than hormone-fueled boys. As a member of the Wing Bind agency, she is highly experienced in facing dragons—mythical beasts that thrive only in the hidden underground world of Reverse London. So when a dark dragon suddenly appears in front of Balgo, Noel and her partner, Ninny Spangcole, are sent to exterminate it before it unleashes its destructive fury upon the unsuspecting London populace.