The adventures of a lonesome princess and meddlesome nun.
(It's recommended you read the serialized manga first, in the related tab.)
Volume 1: The original self-published story.
Volume 2: Pre-serialization extras.
Volume 3: Post-serialization extras.
(Extras take place outside the story. The canon's best described as 'under construction', continuity's nonexistent, and the chapter numbers are simply the order I translate them in, not the order they were drawn. If they have serious plot spoilers I'll mark them as such.)