"Byzantium" was adapted from a play written by Moira Buffini. First off the movie's vampires are not what you expect. These aren't the traditional vampires who prowl at night and sleep during the day. The only thing they have in common with their mythical counterparts is the need for blood and the restriction of being unable to enter private dwellings without an invitation.
The movie follows Clara (Gemma Arterton) and Eleanor (Saoirse Ronan) as they travel around Ireland, leading a nomadic lifestyle. Clara does what she can to provide a life for both Eleanor and herself, and she's not afraid to do anything to earn cash, so that she can provide for them both. She gets her hands dirty, while she protects Eleanor. Eleanor on the other hand is the dreamer and innocent child, overall. However the nomadic lifestyle they both lead begins to wear Eleanor down. She's lonely. She's tired. She yearns to be free of the life they currently lead. Feeding and then moving on, a cyclic life of repetitive non-existence. She's lonely, she's seeking an ear willing to listen to her tale. Hell, she's a teenager, been one for 200 years.
I felt the film's pacing was overall great. There were some moments where time felt like it was standing still, but overall the film flowed smoothly. The visuals were great, especially the outdoor scenes. The dialogue was engaging overall, but some was lost due to the accents of the actors, but that's more my fault I feel for not interacting with native Irish folks. Despite what the trailers may show you, the film's primarily a drama.
The vampires were a refreshing take on the creatures, and while overall not too different, the film was more about Clara and Eleanor as two women trying to survive and etch out a "normal" life, than being monsters of the night.