Spruill (My Soul to Take, 1994, etc.) has a grip on the medical suspense/horror novel far firmer than Robin Cook's. This time out, he sets up what could be the really well-done kickoff novel of a series about hungry hemophages (bloodeaters). Dr. Katie O'Keefe, a hematologist, must crack the resistance of a fantastic new strain of red blood cells to all forms of attack. Some biter-madman in D.C. is ripping open women's throats and leaving drained bodies in churches, beginning with the National Cathedral. Pooled in the ear of his first victim is the killer's own fresh blood -- blood that doesn't dry or clot. The medical examiner sees this non-drying blood as beyond his expertise and calls in Katie to run tests for him. Then more fresh blood turns up on later victims -- blood that will not die! Detective Merrick Chapman, Katie's ex-lover, knows very well who the killer is: his own son, Zane, whom Merrick hasn't seen in 400 years. Both are hemophages -- and Merrick himself is over 900 years old, although be looks only 30 what with his superblood. Centuries ago, though, Merrick gave up murdering victims, learned to drain out enough blood to survive while putting victims in a trance, and began tracking down and imprisoning in an underground vault all the hemophages he could find. But Zane, who has outwitted his father so far, at last plans to meet him face to face and kill him. Meanwhile, Zane discovers that Jenny, a 12-year-old leukemia victim dying under Katie's care, is actually his own daughter -- and he saves her life by feeding her blood orally. Now Merrick must kill his own son -- and granddaughter as well -- if he is to wipe out the scourge. But he has his own young son, Gregory, with Katie, and Zane's threats on Katie and Gregory bring on a Mexican standoff with his father. Terrific plotting -- fresh indeed -- and the hospital background shines in a seemingly unresolvable love story about a man who has already outlived 16 wives and 43 children.