Souji Mitsuka, a first-year high school student, believes that twintails are the pride of mankind. He often spends his time daydreaming and admiring girls with twintails. He has even formed a club dedicated to the hairstyle. However, his obsession does not go unnoticed. When alien monsters invade Earth, they claim all the twintails for themselves. Twoearle, a mysterious woman, asks Souji to fight back with his own twintailed powers. As Tail Red, the twin-tailed warrior, Souji battles against Ultimegil, a ruthless alien organization that wants to colonize Earth and steal attribute power. Souji is joined by twin-tailed fighters Aika Tsube and Erina Shindou. Together, they must conquer the invader's army and safeguard the twintail hairstyle that Souji holds so dearly.