Whatever it is, it is only so different from your past work. It may help if you sit down and try to put together an argument either that you can or you cannot do the work. I would be skeptical and rigorous about it and try to force it into defining exactly what it is that you cannot do. Chances are it is a matter of framing up the work, and in trying to prove the work is impossible, you will probably frame it up and make it be possible.