魔法少女リリカルなのはViVid

Four years after StrikerS, Vivio Takamachi is in her fourth year of elementary school, newly issued an intelligent device of her own called Sacred Heart and able to shift into the adult form of the Sankt Kaiser she was born from. She meets Einhart Stratos, who carries the memories of a different ancient ruler and wants to prove it in a fight, and the argument turns into training. With Nove, Corona and Rio, the two take up Strike Arts and start entering tournament brackets.