In the aftermath of Space War I, where humans and Zentraedi found peace on Earth, a new alien race known as the 'Marduk' emerges in the Solar System. When SNN rookie journalist Hibiki Kanzaki covers the initial clash between the U.N. Spacy and the Marduk, he stumbles upon Ishtar, an 'Emulator' that bolsters the Marduk's combat prowess through song. Taking Ishtar under his wing, Hibiki endeavors to impart upon her the essence of life and civilization. Teamed up with skilled Valkyrie pilot Silvie Gena, they embark on a mission to prevent the Marduk leader Ingues from annihilating Earth entirely.