This unconfirmed report comes from That Hashtag Show, which reveals that the story is put in motion because Black Cat steals from the wrong people, which puts her on everyone’s radar, including Silver Sable.
To that end, Stromm sends Tarantula and Scorpion for her only to find she’s already been caught by Silver Sable.
This report goes onto claims that Silver Sable is most definitely the protagonist of the film, and that her father also has a big role.
Here’s another excerpt from the report, revealing what Black Cat steals that gets her into so much trouble.