Medical thriller set in a decaying Philadelphia hospital for the inner-city poor. In Payback (1991), ex-reporter George Gray got the goods on big-time crooks, then blackmailed them, which he knows is more painful to the crooks than jail time. This time out, George visits an old friend in Clarke Hospital who dies in unnecessary pain. Piqued, Gray smells graft afloat in the halls and checks himself in as a heart-attack victim, a state he knows how to simulate. (Even so, the staff nearly loses him!) George sneaks about, pops open files, and finds that pain-ridden patients are being cheated on their morphine and expensive drugs by being given placebos or useless, cheap substitutes. Someone is racking up millions off patients' pain. And patients are also silently being murdered by a serial killer who stalks the halls--ironically, the hospital's most respected healer, Dr. John A. Walker, the brilliant, tireless, ever-helpful, assistant chief of critical care and white god of the interns and other residents. Sad to say, Walker's a big sickie who gets a kick out of strangling old ladies or jabbing elderly men with naughty needles that stop the breath. What's more, Walker is bedding hospital administrator Nancy Abbott, who runs the drug scam and signs Walker's bodies out to nursing homes that never receive them (they go into pauper's graves) but that bill the government for payments to be split with Abbott and Walker. Meanwhile, George Gray falls in with terrific resident Molly Hale, who helps him break into files. But little does Molly know that Walker regularly etherizes her while she sleeps off-duty in the hospital, strips her down, and enjoys God's handiwork. Walker's motivation as a killer: to experience ``final fear'' in those he murders and overcome it in himself. Less striking than Payback, with Gray cracking secrets faster than a ferret, but the lore about the money-side of hospitals is top-notch.