While experimenting with the anticoagulant EDTA as a possible replacement, Karen discovers that it explodes when combined with vampire blood. She manages to synthesize a vaccine that can cure the infected, but learns that it will not work on a human-vampire hybrid like Blade. Frost and his men attack the hideout, infect Whistler, and abduct Karen. When Blade returns, he helps Whistler commit suicide and arms himself with special syringes filled with EDTA.