well, I don't know about most interesting but certainly the most ambitious. writing a proper mystery requires a very intelligent mind and because most acknowledge it they are also unwilling to even attempt it. this is a story worth reading for more than one reason. I won't explain my specific thoughts about your story because while I wish to encourage you to continue writing I also don't want to even risk it being influenced by my ideas. That would be the third worst scenario for a story such as this right after the story not getting an end. Because of the kind of story, unless you already know what you are going to write it is a given that such a story would take a long time to reach a fulfilling end. really good story, hope you don't decide to abandon it.