Sōji Mitsuka is an ordinary first-year high school boy who has an obsession and greatly loves the "twintails" hairstyle. One day, he encounters a mysterious and beautiful girl named Twoearle from a parallel world when monsters appear in his town who declare that all twintails in the world belong to them. These monsters feed off the "attribute power", the spiritual energy of humans. Twoearle entrusted Sōji with Tail Gear, imaginary armor initiated by powerful twintail attributes. With the armor, Sōji transforms into Tail Red, a twintail female warrior (ツインテイルズ関係者 tsuinteiruzu kankei-sha?), to protect Earth. Now Souji, with the help of his childhood friend Tsube Aika, who can become the twintails warrior TailBlue, must fight in order to protect the peace on Earth.