I've been flown to a temple to kill Alduin but I'm not strong enough to get past Dragon Priest Nahkriin. He's killed me over and over in 2 shots that come faster than I can deal with and so I'm fairly sure there's nothing I can do.
However the dragon that flew me to the temple has disappeared and even if I go back to the spot he dropped me off and call him he doesn't return. I can't fast-travel from this location, either.
I don't have any previous save files as I didn't think this would be an issue. Is there anything I can do?