FIRST, if you haven't seen the movie or read the book "Red Dragon", you won't understand this episode
I get why some people started watching the show without watching the movies first. But at a certain point, they stop being optional and become almost necessary.
Season 1 and 2 run mostly parallel to the movies, giving us original material that works on its own. So, what's the problem with season 3? The problem is it leans heavily on the films. If you haven't seen them, you'll miss the meaning behind a lot of what's happening. That's great if you're a true Hannibal fan, not so much if you are a normal person.
The Number of the Beast Is 666 - Perfection
Like the episodes before it, this one is all about the Red Dragon arc. It's basically the story's near-climax: in the film, Francis Dolarhyde kidnaps Lounds and forces him to see his murders alongside Blake's Great Red Dragon paintings. The show reimagines it brilliantly swapping Lounds for Chilton.
In itself, this episode is a BEAUTIFUL adaptation of the film, a work of art, a magnificent job and a 10/10 episode.
If we take that away, we are left with a good chapter, but not that good.
That's the biggest problem with season 3, its dependence on the movies/books and the reason why the average user doesn't enjoy Hannibal to the fullest.