Hell, a highly mechanical and technical world, was suffering from a new energy crisis as well as the tensing relationship with the Heaven. Mary, an engineering graduate who was taking her internship at the House of Energy along with her friends: a slime , a vampire who had blood-phobia, a zombie cyborg who was interested in human psychology and a moth who collected lamps(and law) were unavoidably mixed up in this great revolutionary epoch that changed their world forever.