Siyo Amano has turned of age to join the war against the Svails, a race of multi-dimensional beings, and the traitors of humanity known as the Rogues. Humanity has been fighting against this extra dimensional threat for 13 years as a defense unit named the Svail hunters. Much like her mother and current guardian, Siyo and her best friend Migro will now take a stand to defend the world of Nebulas.