Ashamed of this display of weakness, she walked a little faster and continued across the bridge to Old Town. Stores and churches and cellar nightclubs were squeezed together like passengers on a crowded train. The young Czechs and foreign backpackers stood outside the pubs, looking bored and smoking marijuana.

Thorn lived on Konviktská Street one block north of the secret prison on Bartolomejská. During the Cold War, the security police had taken over a convent and used it for their holding cells and torture chambers. Now the Sisters of Mercy were back in charge and the police had moved into other buildings nearby. As Maya walked around the quarter, she realized why Thorn had settled here. Prague still had a medieval appearance, and most Harlequins hated anything that appeared new. The city had decent medical care, good transportation, and Internet communications. A third factor was even more important: the Czech police had learned their ethics in the communist era. If Thorn bribed the right people he could get access to police files and passports.

MAYA ONCE MET a Gypsy in Barcelona who explained to her why he had the right to pick pockets and rob tourist hotels. When the Romans crucified Jesus, they prepared a golden nail to hammer into the Savior’s heart. A Gypsy-apparently there were Gypsies in ancient Jerusalem-had taken the nail, and therefore God gave them permission to steal until the end of time. Harlequins weren’t Gypsies, but Maya decided that the mindset was pretty much the same. Her father and his friends had a highly developed sense of honor and their own private morality. They were disciplined and loyal to each other, but they were contemptuous of any citizen-made law. Harlequins believed they had the right to kill and destroy because of their vow to protect the Travelers.

SHE STROLLED PAST the Church of the Holy Rood, then glanced across the street to number 18 Konviktská. It was a red doorway wedged between a plumbing-parts store and a lingerie shop where the window mannequin wore a garter belt and a pair of sequined stockings. There were two other floors above the street and all the upper windows were either shuttered or tinted a hazy gray. Harlequins had at least three exits in their houses, and one of them was always secret. This building had the red door and a second door in the back alley. There was probably a secret passageway that led downstairs to the lingerie shop.

She flicked open the top of the sword carrier and tilted it slightly forward so that the sword handle slid out a few inches. Back in London, the summons had come the usual way: an unmarked manila envelope shoved under her door. She had no idea whether or not Thorn was still alive and waiting in this building. If the Tabula had found out that she was involved in the hotel killings nine years ago, it was easier to lure her out of England and execute her in a foreign city.

Crossing the street, Maya stopped in front of the lingerie shop and looked at the display window. She searched for a traditional Harlequin sign such as a mask or a piece of clothing with a diamond pattern, anything to calm her growing tension. It was seven o’clock. Slowly she moved down the sidewalk and saw a chalk mark on the concrete. It was an oval shape and three straight lines: an abstract suggestion of a Harlequin’s lute. If the Tabula had done this, they would have taken more care and made the drawing resemble the instrument. Instead, the mark was casual and scuffed-as if a bored child had placed it there.

She pressed the doorbell, heard a whirring sound, and saw that a surveillance camera was hidden inside the metal canopy above the door frame. The door lock clicked open and she stepped inside. Maya was standing in a small foyer leading to a steep metal staircase. The door behind her glided shut and a three-inch bolt slid into a lock. Trapped. She drew her sword, snapped the hilt into position, and started upstairs. At the top of the stairs was another steel door and a second doorbell. She pushed the button and an electronic voice came out of the little speaker.

“Voice print please.”

“Go to hell.”

A computer analyzed her voice and three seconds later the second door clicked open. Maya entered a large white room with a polished wood floor. Her father’s apartment was spare and clean. There was nothing plastic, nothing false or shrill. A half wall defined the entryway and living room. The area contained a leather chair and a glass coffee table with a single yellow orchid in a vase.

Two framed posters hung on the wall. One advertised an exhibit of Japanese samurai swords at the Nezu Institute of Fine Arts in Tokyo. Way of the sword. Life of the warrior. The second poster showed a 1914 assemblage called Three Standard Stoppages by Marcel Duchamp. The Frenchman had dropped three meter-long strings on a Prussian blue canvas and then had traced their outlines. Like any Harlequin, Duchamp didn’t fight against randomness and uncertainty: he had used it to create his art.

She heard bare feet moving across the floor, then a young man with a shaved head came around the corner holding a German-made submachine gun. The man was smiling and his gun was tilted downward at a forty-five-degree angle. If he were foolish enough to raise the weapon, she decided to step to the left and slash open his face with her sword.

“Welcome to Prague,” he said in English with a Russian accent. “Your father will be with you in a minute.”

The young man wore drawstring pants and a sleeveless T-shirt with Japanese characters stenciled on the fabric. Maya could see that his arms and neck were decorated with numerous tattoos. Snakes. Demons. A vision of Hell. She didn’t have to see him naked to know that he was a walking epic of some kind. Harlequins always seemed to collect misfits and freaks to serve them.

Maya replaced the sword in the carrying case. “What’s your name?”

“Alexi.”

“How long have you worked for Thorn?”

“It isn’t work.” The young man looked very pleased with himself. “I help your father and he helps me. I’m training to be a master of the martial arts.”

“And he’s doing very well,” her father said. She heard the voice first and then Thorn came rolling around the corner in an electric wheelchair. His Harlequin sword was in a scabbard attached to an armrest. Thorn had grown a beard in the last two years. His arms and upper chest were still powerful and it almost made you forget his shriveled, useless legs.

Thorn stopped moving and smiled at his daughter. “Good evening, Maya.”

The last time she had seen her father was in Peshawar the night that Linden had brought him down from the mountains of the North-West Frontier. Thorn was unconscious and Linden’s clothes were covered with blood.

Using faked newspaper articles, the Tabula had lured Thorn, Linden, a Chinese Harlequin named Willow, and an Australian Harlequin named Libra to a tribal area in Pakistan. Thorn was convinced that two children-a twelve-year-old boy and his ten-year-old sister-were Travelers who were in danger from a fanatical religious leader. The four Harlequins and their allies were ambushed at a mountain pass by Tabula mercenaries. Willow and Libra were killed. Thorn’s spinal cord was hit by a chunk of shrapnel and he was paralyzed from the waist down.

Two years later her father was living in a Prague apartment with a tattooed freak for a servant and everything was wonderful-let’s forget about the past and move on. At that moment, Maya was almost glad that her father was a paraplegic. If he hadn’t been injured, he would have denied that the ambush had occurred.

“So how are you, Maya?” Thorn turned to the Russian. “I haven’t seen my daughter for some time.”

The fact that he used the word “daughter” made her furious. It meant that he had brought her to Prague to ask for a favor. “More than two years,” she said.