The movie functions best for those who viewed and appreciated the initial installment from 2003, and as a continuation, it’s passable. Aside from what seems like an odd choice in casting Sir Derek Jacobi, that part is brief. Kate Beckinsale and Scott Speedman, portraying characters under duress, hurry to locate the incarcerated Lycan "William" before the newly arisen super-vampire "Marcus"—his brother—is able to free him and bring about widespread devastation. The writing feels somewhat awkward, yet the action sequences are well-executed and the film maintains a brisk pace. Like its predecessor, it’s unlikely to appeal to hardcore fans of the horror style, but it does offer the advantage of being thirty minutes shorter than the first, and the personalities involved are appropriately unpleasant and gloomy.

Source on TMDB