Arkayna and Zarya go in search of an ancient and mighty weapon to stop Necrafa and the Spectral Dragon before the entire realm of Gemina is no more. Meanwhile, Emerald and Piper try to fend them off, with the aid of Nova Terron and his fellow Astromancers, without Proxima who is still deeply hurt and dejected upon discovering that she will forever be the "lowly orphan mage".
Four girls are summoned to become the legendary heroes known as the Mysticons. They will undertake a quest to find the Codex.