From Mazaki Tsuzuki, the creator of Magical Girl Lyrical Nanoha.
The official website for the anime of ViVid Strike! has uploaded a video and released the anime´s release date.
While the sory is more or less a mystery, Anime News Networks made a summary of the video, which you can read as follows:
“The video begins with protagonist Fuuka Leventon and her friend Rinne Bellinetta, showing their past as impoverished and bullied children. Fuuka proclaims that she wants to get stronger to protect the things she loves, but that things like happiness and the things she loves eventually get destroyed, so she is done with losing things because she is weak.”
Via: Anime News Network