The story is set aboard the Megazone 11, a different space colony ship fleet from the Megazone 23 in the 1985 original video anime. Megazone 11's master ships are designed as realistic simulations of Earth cities such as Tokyo, and there is also a satellite ship that is designed to resemble a smaller Japanese provincial city around the year 2020.
The protagonist Sakura is an ordinary second-year middle school student who lives aboard that satellite ship. She leads a secret life as part of a singing duo with Eve, a friend she made online. On a master ship, a resistance movement flares up. To achieve independence, they must take control of Tiamat, the system that controls the fleet, but the key to the system was lost in battle 80 years ago. With rumors of its reappearance surfacing, both the resistance and the government are seeking the key. One day, while visiting Akihabara on the Tokyo ship to meet Eve, Sakura is embroiled in the middle of a terrorist attack at the train station. As Eve remotely guides Sakura to safety, Sakura comes across Garland XI, a transforming motorcycle robot mecha that Eve tells her to use.
(Source: Anime News Network)
