Soji Mitsuka loves the twin-tail hairstyle. Following his first day of high school, he and his childhood friend Aika Tsube are enilisted by a mysterious woman named Twoearle to fight an evil force that threatens twin-tails worldwide!

Twoearle answers Soji and Aika's questions about the Tail Gear, including why Soji turns into a girl. Twoearle proposes building a secret support base under Soji's house, but to do so entails serious consequences for Soji's living condtions!

Twoearle gives the others a tour of the newly-completed secret base. When an Elemelian appears, Soji goes into action to stop the attack, but he soon finds himself in over his head. It's going to take another Tail Gear warrior to rescue him!

The Ultimaguil forces find themselves fighting an uphill battle against Twin-Tails, and Dragguildy himself decides to attack in person. Tailred and Tailblue step forward to stop him, but Dragguildy reveals a secret that could change everything!

The Twin-Tail Club is just about ready to start, and Twoearle gives the club's classroom her own touch. With Ultimaguil on the ropes, some new reinforcements arrive to try to turn the tide, but the Twin-Tails add a reinforcement of their own.

Erina's first outing as Tailyellow does not go as expected, and she later confides to Soji that she may not be qualified to be one of the Twin Tails. While Soji tries to work with Erina, Aika must deal with an attack from Leviaguildy and Krakeguildy!