In the village of ninjas, Rui was considered a failure due to her lack of progress in training. As she grew older, she became resentful of her situation and decided to practice on her own. One day, she asked a senior ninja for swordsmanship lessons. Initially reluctant, the senior ninja eventually agreed after witnessing her skills. However, he pointed out that being a female ninja requires not just martial arts but also proficiency in sexual techniques. Determined to prove herself, Rui vowed to undergo any kind of training necessary. From then on, her body was covered in potions while phalluses were inserted deep inside her pussy and anal openings...

くノ一のるいは忍者の村の落ちこぼれ。修行についてこれず雑用係になっていた。悔しかったるいは自分で稽古し実力を身につけた。ある日、るいは上忍に剣術の稽古を頼んだ。初めは渋々相手をした上忍だが、るいの実力に驚く。頭も剣術の腕は認めたものの、くノ一は性技が使えねば役に立たないと言う。るいは「どんな訓練も耐えてみせます」と言い、その日から性技の訓練が始まった。るいの全身に秘薬を塗りつけ、股間とアナルに芋茎をねじり込む…