An egotistical vampire stars in his own movie, and when it attracts a midnight cult audience, goes to see the show…and is captured by mortal scientists.

That's a very convoluted way of saying "When a vampire is captured ..."

What happens next? You've described the setup but not the goal, or stakes of your story.

I left out the fact that the scientists are mortal or did you mean immortal?

When an egotistical vampire is caught by scientists at the screening of a movie based on himself he must........ or his whole world will .......

what does he need to do? Escape? Help?
What will happen if he fails/ is the victor?