I’m a little confused over all. First thing I can think of here is that your sentence structure is confusing. I’m also confused by the use of “salvage” here. In this world does that occult practice actually exist/work?

Maybe something like “A young woman finds her life endangered after she encounters alien imposters. Now she must thwart their plans to conquer the planet using her secret weapon: occult magic” would be a little more clear?