Aoi is just a regular guy until he is kidnapped by Mimori's brother and taken to the Land of Frogs and transformed into a frog when splashed with water.  Mimori, the Frog Princess, goes on a quest with Aoi to help him find the Magic Book to reverse his curse.  Aoi & Mimori are a cute couple, although Mimori is pretty much an airhead (much like Noelle in TnN).  Although they are a cute couple, I wouldn't recommend this anime unless you REALLY like zany filler episode type magical girl series.

This cel of Aoi and Mimori is really beautiful - has great coloring and a beautiful matching background.