Sub genres

Me and Emma, have been discussing the film that we are making, and our ideas we have discovered that they do take on a rather mysterious thriller type film, we want the mysterious element to come in to draw the audience in within the first two minutes, we're planning on doing this by not showing the 'kidnapper' at all except certain things like the silhouette of his body (We would prefer a man as it makes the female look even more venerable, but due to casting problems and males not being available or not wanting to participate in this film, we may have to make it a female kidnapper) and also the hands of the kidnapper as this will give the audience a sense of what gender this person is, so it's a bit of an enigmatic opening which I think would really draw an audience in as that is personally what would draw me in as a viewer. I would also like natural sounds of the sea to open it then eery string/ piano music to set the mood for this opening, I think that would really work and set the mood and allow the audience to realise the genre