Trama

In 1967, a pregnant woman is rushed into a hospital in labor where a C-section is performed on her to save her baby. She dies, but her child lives. Three decades later, the child has become the vampire hunter Blade, who is known as the day-walker, a human-vampire hybrid that possesses the supernatural abilities of the vampires without any of their weaknesses, except for the requirement to consume human blood. Blade raids a rave club in Los Angeles owned by the vampire Deacon Frost.

A seductive woman Racquel (Traci Lords) leads a young man to a rave club. At first, he has fun, but he notices other people staring at him. He casually bumps into the club owner, later revealed to be Deacon Frost (Stephen Dorff), a young upstart in the vampire community. The music peaks when blood is sprayed out from the sprinklers above, and most of the people reveal themselves as vampires. In the middle of the carnage, the armor-clad vampire-hunter Eric "Blade" Brooks (Wesley Snipes) arrives and kills a number of vampires in the club, leaving Frost's right-hand man Quinn (Donal Logue) alive and horribly burned as the police arrive on the scene.

While Quinn's body is being examined in the hospital, he awakens and kills the examiner Dr. Curtis Webb (Tim Guinee) by biting his neck. Curtis later becomes a zombie-like creature, instead of a vampire.

Blade tracks Quinn down to a hospital. Quinn is able to bite a resident hematologist, Dr. Karen Jenson (N'Bushe Wright), before escaping once again after Blade severs his arm.

In an act of mercy, Blade brings the injured Karen back to his lair and introduces her to Abraham Whistler (Kris Kristofferson), his mentor and weapon-smith. Whistler gives Karen garlic essence to fight the conversion to Vampirism. Whistler explains that he and Blade have been waging a secret war against vampires using weapons based on their elemental weaknesses, such as sunlight, silver, and garlic. As Karen is now "marked" by the bite of a vampire, both he and Blade tell her to leave the city.

Meanwhile, returning to her apartment, Karen is attacked by police officer Krieger (Kevin Patrick Walls), who is a familiar, a human loyal to vampires. Blade subdues Krieger and uses information from him to locate an archive that contains pages from the "vampire bible". Karen resolves to study Vampirism and find an antidote before she becomes a vampire herself. In working to find a stable, viable cure, she soon discovers that the anticoagulant EDTA reacts explosively with the vampire infection.

Meanwhile, Frost clashes with his vampire elders of the House of Erebus. He believes that vampires should rise from the shadows and enslave humanity while the elders believe in the subversive rule of (both human and vampire) society through their influence with police, politics, finance and real estate. As Frost and his kind are not natural-born vampires, they are considered socially inferior. Frost is shunned for his radical views and reckless activities.

Krieger informs Frost of what happened, and Frost kills Krieger. Frost studies ancient vampire lore and comes to believe that he can awaken La Magra, the Blood God, to gain absolute power. Together with his minions, Frost kidnaps and mutilates the chief vampire of the region, then kills him by exposing him to the sun. He imprisons the other vampire elders.

Meanwhile, Blade comes upon Pearl (Eric Edwards), a morbidly obese vampire, and tortures him with a UV light into revealing that Deacon wants to command a ritual where he would use 12 pure-blood vampires to awaken the "blood god" La Magra, and Blade's blood is the key.

Blade combats Frost's various minions in an effort to uncover his ultimate plan. After another encounter with Quinn and Frost's lover Mercury (Arly Jover), Whistler explains to a suspicious Karen that Blade's mother, Vanessa (Sanaa Lathan), was attacked while pregnant and that Blade is a half-vampire hybrid with all their superhuman strengths but none of their weaknesses except the blood thirst. Whistler gives Blade a serum to counter the thirst. However, the serum is beginning to lose its effectiveness due to overuse.

Karen successfully develops an antidote to cure herself of Vampirism. She manages to synthesize a vaccine that can cure the infected but learns that it will not work on Blade. Karen is confident that she can cure Blade's blood-thirst but it would take her years of treating it.

While Blade is out on an errand, Frost and his crew manage to invade Blade's lair, kidnap Karen and mortally wound Whistler.

Blade gives the infected and horribly beaten Whistler a gun to commit suicide, then arms himself with a number of weapons and a large supply of EDTA. He storms Frost's penthouse, overrunning the bodyguards, and soon discovers Vanessa, his own mother, whom he believed long dead, in Frost's bed. She reveals that Frost was the vampire that bit her while she was pregnant with Blade and caused him to become the Daywalker. More guards arrive and attack Blade as Frost initiates a long sexual relationship with Vanessa and proclaims himself as creator of their "family". Thunderstruck, Blade is defeated and taken (with Karen) to the Temple of Eternal Night for Frost's blood ritual sacrifice.

Karen is thrown into a pit to be devoured by Webb, who has transformed into a decomposing zombie-like creature. Karen injures Webb and escapes.

The temple antechamber drains Blade's blood and filters it through the ancient channels of the temple. Karen escapes the pit where Frost had put her and feeds Blade her blood, thereby restoring his strength. Frost sacrifices the elder vampires in a mystic ritual and painfully gains the power of La Magra. However, the unintended result was not the awakening of the blood God, but the culmination of the dead elders' souls that fought absorption as the energies consume Frost's body. Vanessa attacks Blade forcing him to kill her.

In the melee, Karen secures a shotgun from a guard, shoots him dead and kills Mercury with concentrated garlic spray. Blade furiously cuts through Quinn and Frost's minions before engaging Frost. Frost's new powers make him immune to Blade's conventional weapons, so Blade injects him multiple times with EDTA, causing Frost to explode. As the pair leave the temple, Karen offers to cure Blade, but he chooses to forgo the cure in order to continue hunting vampires and asks her to develop a better serum. An epilogue finds Blade observing a vampire attacking his date in Russia, indicating that Blade's new campaign has spread into Europe.