I am not sure Nanami's characterization makes any sense with the characterization previously established; will have to check. I still find the characters here much less endearing than in Karakuri Odette, although the art is better. No catfish princess this time. :( Also, the Dragon King's underwater palace was pretty underdrawn and the character design wasn't as quirky and unusual as the best of the series' reimaginings of ayakashi.
The plot is standard romantic complication hijinks. Whatever.