La lucha milenaria entre depredadores ha adoptado nuevas dimensiones de violencia. Ha nacido una nueva raza en nada comparable a ninguna otra conocida. Traicionada por los de su propio clan, la guerrera vampiro Selene (Kate Beckinsale), busca venganza. Para ello, decide descubrir la verdad sobre la identidad del primer Inmortal verdadero. No es Marcus, el rey de los vampiros como se creía, sino Alexander Corvinus, padre de Marcus y de su hermano gemelo William. Selene y el híbrido Michael (Scott Speedman), protagonistas de un amor prohibido, lucharán juntos contra el poderoso Marcus, quien está decidido a liberar a su hermano preso y usar la sed de sangre de éste para llegar a dominar el mundo.

As the adventure continues, the saga of war between vampires and werewolves. Selene, the vampire "death dealer" who's now fighting to stop the release of the original "Lycan" werewolf, William from the prison that's held him for centuries. As we learn from the film's action-packed prologue, William and his brother Marcus began the bloodline of vampires and werewolves, and after witnessing centuries of warfare between them, their immortal father Corvinus now seeks Selene and the human vampire/lycan hybrid Michael to put an end to the war perpetuated by Victor, the vampire warrior whose betrayal of Selene turns Underworld: Evolution into an epic tale of familial revenge.