The gun weighed heavy in his hand. The last time Detective Mac Granger unholstered his piece was three months ago at the shooting range when he drilled the heart of the paper target nine out of ten shots.

It was a Thursday night in September. Mac and his partner, Detective Sheila Hartman, had been on their way to a homicide investigation in north Denver when a squawk came over the radio in their unmarked car: "Officer in need of assistance."

Headed north on Park Street, they had just passed the homeless mission with the red neon Jesus Saves sign. They were close to the location given and arrived first on the scene — a dark, deserted city street lined with two-and three-story buildings. The crumbling bricks were stained by years of greasy soot from the nearby railyards.

Three other cars were carelessly parked near a run-down warehouse. The door to the loading dock gaped open. Inside the warehouse, it was pitch-dark.

As Mac emerged from the car, gun in hand, the night breeze whipped around him. A crumpled sheet of newspaper rolled down the street like a tumble-weed. From ten blocks away, he heard a resounding cheer from the baseball fans at Coors Field where the Rockies were playing a night game. Home run.

From inside the warehouse, gunfire exploded. Several shots in rapid succession. A semiautomatic weapon. This sounded like something bigger than he and his partner could handle. "Stay back," he ordered Sheila. "Other patrol cars will be here in a minute."

She shot him a glare. Sheila was inexperienced and willful. She could be a real pain in the ass.

"Police," she yelled. "Throw down your weapons and come out with your hands up."

"Come and get us," was the response.

"Us," Mac said pointedly. "There's more than one." Ignoring him, Sheila yelled again. "You're surrounded. Give up now."

He cursed under his breath. If the bad guys came onto the street, they could see at a glance that the only cops on the scene were the two of them. Frankly, he and Sheila weren't real impressive when it came to firepower.

"Stay here," he said to her.

"Maybe I could circle around and —"

"Stay."

The woman was impossible. They wouldn't even have been in this area if they'd gone directly to their crime scene in north Denver instead of stopping once because Sheila had to pee, then again because she wanted a latte.

Mac ran toward the loading dock and flattened himself against the brick wall. If anybody came out, they'd be caught between him and his partner.

A bulky figure charged through the open maw of the loading dock and leaped down from the ledge. He landed on the pavement only a few yards away from Mac.

"Drop your weapon," Mac ordered. "Raise your arms."

Immediately, the man obeyed. Mac grabbed his arm and flung him face-first against the brick wall. It was Vince Elliot, an undercover vice cop.

Vince gave no sign of recognition. Even in the heat of confrontation, he didn't break cover.

As Mac cuffed him, he whispered, "This is a drug sting gone bad. Be careful. I want to take these guys alive."

Sheila abandoned her position and came toward them. Dumb move. The worst thing they could do in this situation was to stand together and get mowed down by one blast.

Angrily, Mac motioned for her to go back. He could hear the sirens of approaching patrol cars. Backup was on the way.

Sheila made a confused gesture. Then she stamped her foot and checked her wristwatch as if she were late for a manicure appointment.

Four armed men emerged from the dark warehouse. The one in front aimed directly at Sheila.

Mac had to protect his partner. He fired once, point- blank. The man with the gun went down.

Time froze. Everything went into slow motion. Mac shoved Vince Elliot to the pavement and stepped in front of him. He looked into the faces of the armed men who turned toward him. He saw panic in their eyes. When they returned fire, he imagined the bullets poised in midair. The thunder of gunshots resounded against brick walls.

It occurred to Mac that he might die right here on this cold city street. A fitting place. Though he had been born and raised in the mountains, this was where he belonged.

He got off another shot, aiming low. He didn't want to kill these guys. Another man fell with a scream.

The others ran toward their car. "Freeze," Sheila yelled. "Police. Freeze." The two remaining men dropped their weapons as several patrol cars arrived simultaneously. It was over.

Mac felt a sharp pain in his shoulder and looked down. Blood seeped through his tan sports jacket. He'd been hit.

ABBY NELSON leaned her back against the slender white trunk of an aspen tree and looked up through a canopy of sunlit golden leaves. A fresh wind rustled the boughs, and she glimpsed the clear, blue Colorado sky. Fantastic! This was a truly cherry assignment.

Her last undercover job as an FBI special agent had been in an inner city back east where she was supposed to be a pregnant runaway with a drug habit. Needless to say, her companions were the dregs of society — slimeballs, creeps and heinous criminals, many of whom were going to be locked up for a very long time thanks to Abby's efforts.

But this time? Way better! When she was told that she was going undercover to an FBI safe house in the Colorado Rockies, Abby couldn't believe her luck. She inhaled the crisp clean air and reveled in the spectacular scenery. This was practically a vacation.

Her undercover identity was Vanessa Nye, a protected witness who was waiting to testify at a high-profile case in Los Angeles involving the Santoro crime family. The real Vanessa was an unabashed gold digger who traded on her outrageous sexuality, andAbby had disguised herself accordingly. She dyed her hair platinum blond, heaped on tons of makeup and slithered into skintight clothes. The worst part of her Vanessa outfit had to be these wretched spike heels that were digging holes in the soil beside the aspen trees. She wasn't looking forward to the mile-and-a- half hike back to her bedroom at the safe house.

Her solitude was interrupted when a sturdy-looking woman on horseback rode toward her. Julia Last was the special agent in charge of the FBI safe house known as Last's Resort. She was the only person on site who had been informed that "Vanessa" was a cover for Special Agent Abby Nelson.

Julia gave a friendly wave. "Want a ride?"

"You bet I do."

Julia stared pointedly at the purple high-heeled shoes. "When you get into an undercover role, you don't kid around. How do you stand in those things?"

"Not very well," Abby admitted. "It's not something they teach at Quantico."

Julia flicked the reins and directed her dappled gray mare close to a granite ledge. "Climb on the rocks, then throw your leg over the rear behind the saddle."

Abby moved carefully. Her snug designer slacks were partly spandex, but she didn't want to take a chance on stretching them out and ruining her look. "If I were the real Vanessa, I'd never do this."

"If you were the real Vanessa, I wouldn't have let you wander off by yourself." As soon as Abby was settled, Julia nudged her horse into a steady, rolling walk. "We take security for our protected witnesses very seriously."

"Have you had problems?"

"Not from outside," Julia said. "Our location is remote enough to provide natural protection. As far as anybody knows, this safe house is just another mountain resort. The problems come when witnesses get bored."

"Cabin fever. They want to take side trips to Vail, right? Or invite a friend to visit."

"That's right." When Julia nodded, her curly brown ponytail bounced. "Sometimes we indulge them with supervised outings."

"And you've only got the other two agents working with you?"

"On a rotating basis. This safe house is considered a prime assignment until they get here and find out that their responsibilities include chopping wood, mucking out the stalls for the horses and making beds." She tossed a grin over her shoulder. "I take a certain amount of satisfaction seeing these macho agents doing housework."

"I'll try not to gloat when I see them with feather dusters. What's the name of the young one?"

"Roger Flannery. Nice kid."

Abby tucked a wisp of platinum hair behind her ear. "How many other people are staying here?"

"Two," Julia said. "We refer to them as guests. Both older guys. They've been here for nearly a month."

"I thought the protected witnesses got shuffled more frequently so nobody can get a bead on their location."

"I didn't say they were both witnesses."

Abby already knew that the safe house was used for more than protected witnesses. Sometimes, the feds held high- level meetings here. Sometimes, this idyllic mountain setting provided a place for rest and recuperation for injured agents and cops. "The guy I'm interested in will show up this afternoon."

"The homicide detective from Denver."

Mac Granger was Abby's assignment. He was a Denver cop who had been wounded in a drug sting and was suspected of being on the take which — in Abby's opinion — made him the lowest of the low.

According to her information, he'd wounded an undercover FBI agent at the sting — an agent Abby knew very well. Leo Fisher was her former fiancé.

Though their breakup had been exceedingly nasty, she didn't wish Leo dead. At least, not most of the time. She'd been glad to hear that he was expected to recover from the bullet wound in his leg.

As she rocked on the rump of the horse and watched the landscape unfolding around her, a familiar twinge of regret brushed through her. Too bad things hadn't worked out with Leo. For a while, she'd thought she loved him.

But she wasn't sure. Because they were both undercover agents, it was possible they were both playing at being in love — acting the way they thought people in love ought to behave. With all her under-cover identities, she sometimes forgot what it meant to be real.