[Note: This is an adaptation of the 2002 movie "Blade II", and as such, takes place in the cinematic world established in the film series, as opposed to the Marvel Universe.]
A new breed of vampire stalks the night in Prague, a bloodthirsty creature that preys on other vampire as well as humans.
Elsewhere in the city, Blade has, after three years of searching, tracked down the body of his partner and mentor, Abraham Whistler. Although Whistler had apparently killed himself after a vampire attack, his body was stolen by them, and kept alive in a twilight state, not quite vampiric. Blade returns with Whistler to his warehouse base, providing his friend with a cure, over the objections of Scud, Blade's new assistant/mechanic/engineer.
Before long, a pair of vampires displaying ninja-style skills invade the warehouse, but, after a brief conflict, offer Blade's team a truce in a bid for help. The pair, Nyssa and Asad, lead them to the Caliban Industries facility, a front for a vampire stronghold. There, they are introduced to the leader, Damaskinos, Nyssa's father. He asks Blade to work with his elite vampire strike team, the Bloodpack, to track down and eliminate the new vampire breed, which he calls Reapers.
Blade agrees, and later, they enter the House of Pain, a vampire night club. Before long, they are set upon by Reapers, who prove extremely difficult to kill, with UV light being the most effective weapon. One of the Bloodpack succumbs to a Reaper's bite, and is dispatched by Reinhart, another Pack member. Meanwhile, Blade duels the original Reaper, Nomak, to a stalemate when the latter escapes to avoid the dawn.
After an autopsy of a fallen Reaper reveals their unique anatomy to the team, they agree to conduct a search-and-destroy mission in the sewers below the club.
Soon, they are underground, armed with their individual weapons as well as UV grenades. The begin to wipe out the Reapers they encounter, but before long, they realize they have underestimated their enemies' numbers. Several of them die in the struggle, leaving Blade, Whistler, Nyssa and Reinhart to face impossible odds. Blade orders the others to escape down one tunnel while he goes to set off a UV bomb that succeeds in wiping out the Reapers, but also injures Nyssa and Reinhart. Then, armed vampire troops rush into the sewers to capture Blade and Whistler.
They are returned to Caliban, where Damaskinos reveals that the Reapers did not evolve naturally, but were bioengineered by his scientists to become the next stage in the species. Scud reveals himself as a familiar, sent to spy on Blade, and Blade kills him before being subdued by Reinhart.
Blade is then nailed to an autopsy table where Damaskinos intends to drain his blood for use to improve the Reaper strain by making them invulnerable to sunlight. Nyssa, who had come to share a mutual respect with Blade, objects to this betrayal, and also demands to know the connection between Damaskinos and Nomak. Her father explains Nomak is her brother.
It is then Nomak appears, leaving a trail of dead vampires as he makes his way to his father. In the confusion, Whistler frees Blade, who plunges into a blood pool, replenishing his strength. He defeats a squad of guards, then kills Reinhart.
Damaskinos attempts to escape with Nyssa, but are trapped by Nomak as he locks down the facility. Nomak kills his father, then bites Nyssa. Blade arrives and the two engage in a brutal fight. Blade manages to pierce Nomak's heart with his sword, and the Reaper burns to ash.
The bitten Nyssa asks Blade to take her outside to see the sun rise, so she can die as a vampire. Blade complies, and she burns to ashes in his arms.
Before long, Blade resumes his crusade.