The story arc is somebody who is a like knows how to be a good person but doesn't have a reason to be until some oh yeah something comes along and kind of jostles them I dig that awake. Vimes as he is trying to investigate stuff about dragons he goes to this lady Sibyl Ramkin who raises little swamp dragons as pets for other aristocrats. She's the only one who would know anything about dragons they reckon so she gets involved in his investigation. The dragon then sort of traces back the path that he had been summoned by and uses it to like a manifest himself, becoming an independent king.