Sota Mizushino was watching the anime "Elemental Symphony of Vogelchevalier" in his room when suddenly, Selesia Upitiria, a character from the anime, and a mysterious girl dressed in a military uniform appear in his room. Sota gets caught in the middle of their battle and follows them to Yoyogi Park, where Meteora Österreich, a character from the game "AVALKEN of Reminisce", suddenly appears.
