A legendary ninja in the Kiryu Clan, Kenzan, engineers his disappearance in front of his ten-year old son, Kagerota, telling him that they will only meet again when Kagerota has grown up and polished his own ninja skills. Upon reaching maturity Kagerota has become a rogue ninja that is hunted by agents sent by the aged clan leader, Katsuragi, to get back the scroll Kenzan is thought to have taken with him which details how to shape-shift and vanquish enemies. Finding a cat that has a red nose like Kenzan, Kagerota deduces that his father has shape-shifted himself into the cat, so he calls it "Father" and begins to look after it as he dodges clan agents including the female ninjas Momiji and Tsubame.

陽炎太從小時候就被傳奇忍者父親丟在野外獨自生活，父親說在他忍者技術大成的那天，就是他們的重逢之時。成年之後的陽炎太遇見了與父親有著相同紅鼻子的胖橘貓，他深信著父親用了忍術秘傳易容術陪在自己身邊。與此同時，忍者宗族長老為了能得到祕傳忍術卷宗，派出了兩名女忍者紅葉與燕，欲捉捕陽炎太完成忍術傳承。陽炎太與「父親大人」，就這樣開始了一段啼笑皆非的逃亡生活。