That sounds very strange and wonderful. I think the only films by David Manners I've seen are Dracula, The Mummy, and The Black Cat, and he plays basically the same clueless romantic lead in all of them. Helen Chandler's Mina also isn't super interesting (especially compared to Lupita Tovar in the Spanish-language version), though there may be glimpses of the strangeness you describe in the scenes where Mina acts under Dracula's influence. Having only seen these performances by Manners and Chandler, I'm very curious to see them in The Last Flight. (I'm also curious to see your reaction to Dracula; I've seen it many times, but saw it on a big screen for the first time last weekend, which was quite wonderful. Dwight Frye's Renfield is probably my favorite thing about it.)