Tales of the Frog Princess, book 8: A Prince Among Frogs
E.D. Baker2010

Princess Millie and her fiancé, Audun, are busy preparing for their wedding when trouble starts brewing in Greater Greensward. Millie's baby brother, Felix, has been kidnapped and is trapped in a swamp full of other frogs. With all the adults busy fixing problems elsewhere in the kingdom, it's up to Millie and Audun to find him—but they need all the help they can get to fight the family's oldest nemesis, the angry wizard Olebald. From the deep blue sea to the soaring skies, our two heroes will stop at nothing to get their families back together and banish all the troublemakers for good.

Titre original : Tales of the Frog Princess, book 8: A Prince Among Frogs (2010)