And everything else argued against innocence.

In his request for covert assistance from Chicago, the New York detective had traded on his reputation as a shabby dresser with a low bank balance; these hallmarks of a dead-honest cop made his badge shine in the dark. There were even rookies in the state of Illinois who had heard of Riker. And he planned to destroy the best part of himself-for Mallory’s s ake.

He stopped for a red light and closed his eyes. More frightening than the corpse in Mallory’s front room was the wall of telephone numbers in her den. If nightmares had triggered her childhood calls, then Riker had to wonder, Kid, what are your dreams like now?

The car’s engine idled as Mallory pulled an old letter from her knapsack. This was only ceremony; the pale blue ink was illegible by street lamp, and the discolored paper was falling apart at the folds. The opening line, committed to memory, began with green lions-and there they were. The matched pair of statues flanked the broad steps of the Chicago Art Institute on Michigan Avenue, and they pointed the way down Adams Street.

The letter went on to say, “There are travelers who recognize this intersection of commerce, high art and green lions as the beginning of the Mother Road, though its original starting point was elsewhere. Historically a shifting highway, now it’s vanishing, reduced to a patchwork of interrupted pavement scattered through pieces of eight states, all that remains of a fine romance with the journey and the automobile.”

Mallory was not of the romantic ilk. The night was wet and cold, and she was disinclined to wax poetic on the American car culture.

Angling the headlights into the darkness, she anticipated police barricades, but these wooden sawhorses bore the name of a Chicago contractor. The crime scene was also a construction site, and this was one detail that was not picked up on her police scanner. Her high beams lit up concrete segments of an old water main stacked beside earthmoving equipment. The late hour and a recent storm had cleared the area of witnesses-not that she cared. She killed the engine and left her car to push one of the barricades aside, and now she walked toward the bulky machines that might hide more obstructions.

Wooden planks spanned two of the traffic lanes, and an orange sign warned her of a large hole beneath the boards, but all that interested Mallory was a large sheet of crumpled blue plastic nudged along the ground by the wind. At each corner was a crude tear where the thin material had been ripped loose. She easily found the former moorings of this blown-down canopy; bits of twine were still tied around lampposts and signs. Other tarps, ones belonging to the contractor, were made of light canvas and sized to cover machines. The workmen would have needed no cover; they would have been gone before the late-night storm; road repair might carry on in the dark-but not in the rain. And this flimsy material was not something a crime-scene van would carry. It could serve only one purpose here-a temporary cover for a killer who wanted privacy from high windows and the elevated train that bisected Adams Street.

The killer had brought his own tarp to the party, and the crime-scene unit had failed to confiscate this evidence, mistaking it for construction debris.

Mallory pulled out her cell phone and placed a call to Chicago PD. Failing to introduce herself, she demanded the name of the detective who owned this homicide.

“Kronewald?”

We ll, that conjured up a familiar face. She could picture the old man turning a heart-attack shade of red when he found out what the CSU team had left behind-plastic, a fingerprint technician’s wet dream. “Tell him to collect the blue tarp. It belongs to the killer, not the contractor.”

The desk sergeant was asking for her name as she ended the call. Mallory, never inclined to waste words, was busy just now. One more barricade to go, and then she must be on her way before Detective Kronewald turned up to find a New York cop on his little patch of turf.

The blue plastic was on the move again, and she picked up a piece of concrete to weight it down. The wind had carried it clear of the rough boards that patched the contractor’s hole, exposing yellow tape laid down to form the crude shape of a body. And this made her smile.

The Chalk Fairy strikes again.

In large towns and small ones, every now and then, a homicide team would arrive at an otherwise pristine crime scene and find this outline drawn with a piece of chalk or a crayon borrowed from a child. An angry detective would then demand to know which helpful idiot had committed this travesty, and guilty-looking young rookies in uniform would flap their arms and fly away with cries of “I dunno. It wasn’t me.”

It was a mystery.

Tonight, Mallory could easily guess the Chalk Fairy’s secret identity. It could only be the scared young cop who had given up bizarre details of this crime on an all-too-public radio frequency-forgetting everything taught at the police academy. Oddly enough, he had remembered the one thing he should never do, a lesson of television cop shows. Instead of chalk for his outline of the victim, he had used crime-scene tape, tacking it down with construction-site nails when it failed to adhere to wet wood. Thus, with every good intention, the first officer on the scene tonight had butchered the evidence of other nails used by a murderer to stake a human body to the ground.

Damn Chalk Fairy.

She should be leaving now. How much time had passed since her chat with the desk sergeant? A police cruiser could only be minutes away. Instead of heading for her car, she pulled out a penlight and trained the beam on the killer’s nail holes, the ones inside the taped outline, where the victim’s wrists and ankles had been pinned to the boards. Scattered at her feet were nails like the ones used to make the wooden road patch. When she dropped one into a hole, it was smaller than the opening.

This killer’s murder kit had duplicated onsite materials. Obviously a cautious one, maybe he was also a long-range planner, and his plan may have begun long before the city of Chicago decided to rip up this street. So he had packed his kit with bulky plastic, heavy iron nails-and bones. How that rookie cop must have freaked to see those bones attached to a fleshed-out corpse. Now the Chicago police had a double homicide, old bones and fresh kill, one corpse short of the body count needed to call this a serial killing, yet Mallory had no trouble making that call with only the evidence laid out before her.

She stared at the taped outline that described the arrangement of the body, an invitation to a game. It had been laid out for show with one arm extended, pointing down the road to say Follow me.

A distant siren was screaming, coming closer, and yet Mallory did not hurry. When one more barricade was moved aside, she did not run-she walked back to the car, settled in behind the wheel and started up the engine. The siren was louder, almost on top of her. After depressing a button on the face of the speedometer, her trip monitor went down to zeros.

And now it begins.

The car rolled through the crime scene, continuing west on Adams Street for a while, nearly overshooting the turn for Ogden -just as the letter had predicted. Mallory carried no maps, only a route created from words that were written before she was born. Dropping down, southwest through Cicero, she searched for the next landmark. According to the letter, “He’s so big, you can’t possibly miss him.” Yet there was no sign of a giant folk hero holding a large hotdog. She retraced long stretches of Ogden on both sides of Lombard Avenue, where the fiberglass statue belonged, but it was no longer there. Her next landmark was far from here, way past the town of Joliet. She was heading toward a road by that same name and an open field that might not be there anymore. An entire town could have grown over the old baseball diamond since the first yellowed letter was written to say, “One day you won’t be able to get here from there. This is a time as much as a place, and even the stars might be gone. That’s the problem with progress. Can’t see stars by city lights.”