Sōji is an ordinary high school student with an extraordinary love for pig tails (or "twin tails"). One day a mysterious girl from another universe named Thouars appears in front of him. At the exact same time, monsters begin attacking the city where Sōji lives, declaring they will drain the world's energy in the name of the Twintails. Sōji receives a powerful armor from Thouars called "Tail Gear" which transforms him into a female Twintail warrior named Tail Red.
Usagi Tsukino was a normal second-year middle school girl whose own life changes one day when she encounters a black cat. The cat's name is Luna who can talk and bears a cresent moon on her forehead. Luna tells Usagi that she is the chosen guardian of justice with the power to transform into Sailor Moon. Usagi now has a new responsiblity which is a mission to find the Illusionary Silver Crystal as well as the other chosen guardians to protect the Moon Princess. During her mission, she must deal with various enemies sent by Queen Beryl who is also after the Illusionary Silver Crystal.
In Oshima the happy, carefree 14-year-old Akane Isshiki lived a poor but well-loved life together with her reliable little sister, Momo, who does all the housework, and her grandfather, Kenjirō, a genius inventor who only created useless devices. When the weather is clear, they can see the artificial island, Blue Island, across the sea. In the center of that island rises the revolutionary Manifestation Engine, a discovery that solved the world's energy problems, and leads to some major problems.