I enjoyed coming back to visit Club Shadowlands, and the Masters there. In Dark Citadel we're treated to a beginners' class. Kari arrives with her boyfriend - who's a real asshole - and ends up dumping him when he oversteps his bounds. Luckily, Master Dan is there to help her explore her desires and questions about BDSM.
Kari's a school teacher that isn't quite sure if she should be even doing this. She's interested, more than, but at the same time she can't figure out what possessed her to agree to stay and play with such an intimidating, experienced Dom. I really like how she's secure in herself; Kari may not always be comfortable with her body, but she knows what she deserves and isn't afraid to demand it.
Master Dan hasn't let anyone get close since his wife's death several years ago. He doesn't want to risk letting anyone into his heart, but he's incredibly caring and the instant connection between Kari and himself is hard to deny - not that that prevents him from seriously messing up a few times.
Dan's own issues lead him to hurt Kari a couple of times - without meaning to - and I love how she calls him on it and tells him that she deserves more.
Dark Citadel is another novella so there's not really an outside plot, simply Kari and Dan getting to know each other, themselves and decide that they deserve happiness - something they can find with each other.