You have to read it through too many times to make heads or tails of what the story is about. This is a really bad sign for what is meant to be a single sentence that gives the reader the basic concept and conflict of your story.

It’s also very vague.

What is the event that forces her to take this action so drastically at odds with who she is? It must be massive, right? For someone afraid of water to react to something by jumping in a submersible then a powerboat? What is ‘her birthright’ and how has it been ‘stolen’?

Can seas BE mountainous?

If these Germans are so far away, in what manner have they been tormenting her? And what information are they going to reveal that she has to silence them? What are the stakes, and what is the hurry?

Are her country of origin and her gender really the most crucial and relevant descriptors of her as a character?

I can’t even suggest how I think this should be re-written because from my perspective the story is too broken.