The full story
In 1967, a pregnant woman is bitten by a vampire and dies giving birth. Her son survives with a vampire's strength and senses and none of its weaknesses except the thirst. Thirty years later he is Blade, the "Daywalker," hunting vampires with silver, garlic and ultraviolet light alongside his mentor and armorer, Abraham Whistler, whose serum keeps Blade's own craving for blood in check.
Blade raids a vampire club owned by Deacon Frost. One burned survivor wakes in a hospital and feeds on hematologist Karen Jenson, and Blade brings her to Whistler. Frost is a turned vampire, not a pureblood, and the elders who run the vampire world look down on him for it. He has the sun kill one of them and takes the rest prisoner, because ancient texts have shown him how to awaken La Magra, the vampire blood god, inside himself: twelve purebloods, and the blood of the Daywalker.
Karen finds that the anticoagulant EDTA makes vampire blood explode, and makes a cure for newly bitten humans, though not one that can help Blade. Frost's men raid the hideout, bite Whistler and take Karen. Blade leaves the dying Whistler a gun so he can end his life before he turns. Then he goes after Frost, and finds his mother Vanessa alive, a vampire at Frost's side. Frost was the one who bit her.
At the Temple of Eternal Night, Frost drains Blade's blood and becomes La Magra's vessel. Karen lets Blade drink from her to get his strength back. Blade kills his mother, cuts through Frost's followers, and kills Frost by injecting him with EDTA, which makes him swell up and burst. He turns down Karen's offer of a cure and asks her for a better serum instead. In the last scene, he's in Moscow, hunting another vampire.