Magical Girl Lyrical Nanoha ViVid is set four years after the events of Magical Girl Lyrical Nanoha StrikerS, during which magical girl Nanoha Takamachi rescued and adopted a young girl named Vivio, who is the central character of the new series. After entering her fourth year of elementary school, Vivio is given her own intelligence device, Sacred Heart, and gains the power to transform using her adult form "Vivid". She then enrolls in a combat-oriented magic school where she meets Einhart Stratos, a girl from a prestigious magical family who studies at the school. The two become close friends as they train together to refine their powers.
The story follows Vivio as she learns more about her origins and develops relationships with those around her while mastering her magical abilities. Along with Einhart's help, she aims to become an even stronger mage by participating in various tournaments and battles. As the story progresses, Vivio discovers secrets about Einhart's past that could have a major impact on their future together.
