カオリは雨の中を歩いているとき、一匹の蛙を助けた。その夜、眠っていたカオリは、蛙の鳴き声で目覚める。ガラス戸越しに映る、蛙の影。だが、カオリが追っていくと、そこにはひとりの美剣士が立っていた。「蛙ノ介」と名乗る美剣士は、カオリが助けた蛙が変身した姿だという。蛙ノ介の美しさに、魅せられたカオリは……。
When Kaori was walking in the rain, she saved a frog. That night, Kaori was asleep when she woke up to the sound of a frog's croaking. The frog's shadow is reflected through the glass door. But when Kaori chases after it, she finds a beautiful swordsman standing there. The beautiful swordsman, who calls himself "Kaerunosuke," is said to be the transformed form of the frog Kaori saved. Enchanted by Frognoske's beauty, Kaori goes to .......
