This movie is based on a young adult novel, (albeit with major changes to the plot) and if you're looking for a traditional, gory werewolf film, look no further. This is in fact a Romeo and Juliet / West Side Story sort of film, the young man (Hugh Dancy) being the black sheep of his family, while his love interest (Agnes Bruckner) is a wolf in girl's clothing. You don't get much more opposite than carnivore and meat, but attract they do, much to the dismay of her pack, especially the leader, Gabriel (Olivier Martinez).
In this film, werewolves in their human form jump around like crouching tigers and hidden dragons. They transform at will by leaping or twisting creatively through the air, emerging in lupine form from a blazing streak of luminous light. The sight or smell of blood causes their pupils to glow with a weird yellowish tinge, and as you know, amber means "caution".
As Duran Duran might have sung in "Hungry Like the Wolf":
Sharpen the silver, light up a pyre Wolves in the city, eyes are on fire Do do do do do do dodo dododo dodo Aiden, he wants her, shows her a sign But when he's bleeding it sends chills up her spine Do do do do do do dodo dododo dodo
Other than Bruckner, the acting isn't the best, even for a werewolf movie, and you'll find it's less like "An American Werewolf in London" and more like "Teen Wolf".