It isn't that hard to pick up. Originally it was a dark urban fantasy horror setting where all the things that go bump in the night are real and fighting to survive. The world is the real world but with monsters lurking in the dark places.
The other factions out there are Wraiths(ghosts), Mummies, Demons, Changelings, and Hunters(mortals who know about monsters...literal inspiration for the Supernatural tv series.)
Werewolves and Vampires have a built in hatred so I think they make a great pair for this game. If you've seen the Underworld franchise of movies you get the gist. Werewolves are territorial pack hunters and see vampires as undead abominations that need to be destroyed. Vampires are bloodthirsty murderers who see werewolves as big vermin, beneath notice if they weren't so dangerous.