He pulls into the parking lot of a colorless two-story warehouse draped with a banner for Bay Area Fitness. He's early enough to snare his favorite spot, right next to a Chevy SUV with tinted windows and the vanity plate W8 GURU.

He leaves his shades on the dash, the thunder from the freeway hitting him when he opens the door. He's wearing gang-neutral colors -- black sweats, black tee and black shoes (all Nike) -- 10 grand of gleaming gold on one wrist, a diamond ring and a $7,000 Rolex. Ronnie Gerald Allen doesn't do the locker room and doesn't carry a bag. He begins with chicken teriyaki in the gym's cafe, watching a bit of the box. At 11 A.M. he saunters through an open door into a body-builder's heaven and hell -- a cavernous warehouse nearly as long as a football field and crammed with factory-style rows of barbells and machines. Massive steel roll-down doors pass for windows, and black rubber mats pass for a floor.
Greg Anderson, San Francisco Giants superstar Barry Bonds's personal trainer and the guy with the W8 GURU vanity plate, awaits him. Anderson doesn't look like much -- he's short and squat, with cropped brown hair and a dimpled chin. His long sleeves and sweats make it hard to gauge his bulk. He starts off with Ronnie by targeting his shoulders, requiring four subtle movements -- more than 40 reps -- just for one major muscle group. Anderson insists they execute each lift at an excruciatingly slow pace -- 10 seconds so demanding that by the end of a 10-rep set the trainer is cradling Ronnie's shaking triceps, helping him finish. After a ferocious round of weights and sit-ups, it's upstairs onto the treadmill for a 45-minute slog and then another 45-minute churn on the bike.
"Good workout," Anderson tells the sweat-drenched Ronnie. "We're going to hit it hard tomorrow."
Ronnie can barely think about tomorrow. The week's workouts have taken their toll -- on his way out he grabs at a twinge deep inside his shoulder that feels like a torn muscle. But there's no stopping now, because Ronnie G. is on a mission. He is actually Iran White, a top undercover cop sure that he's about to crack the biggest case of his career. He has worn a wire and kept a Glock stuffed in his waistband for two months, all in a daring attempt to get close to Anderson and, ultimately, to Bonds himself. White is armed because he's looking for juice: He's on a hunt for steroids.
That evening White has a headache he can't shake. His wife nods off, but White sits up in bed watching television, his gun on the nightstand. On the wall hangs a photo of him with fellow agents posing in front of a light armored vehicle used to ram a drug dealer's gate. He stares at it as the hours pass. Sometime in the early morning he feels a chill go up his spine. Then he has trouble breathing, as if someone has punched him in the chest. He tries to sit up, but his right side won't cooperate. He shakes his wife awake and barely gets the words out. "Call 911," he says, his eyes full of despair and surprise. "I think I'm having a heart attack."
The words tumble out like pieces in a jigsaw puzzle. I'm dying, he thinks. Then something worse: I can't move. I can't talk -- I'm paralyzed.