She had no way of knowing it, but members of her family had been answering that call for nearly 450 years.

Monaco to Casablanca.

Overland, it was a journey of more than a thousand miles, across defended borders, through countries in conflict. And then she’d still need to traverse the Strait of Gibraltar to get to Africa.

Travel by ship would be more direct, but the Mediterranean was dangerous during wartime. More to the point, boats were slow. By the time she reached Casablanca, General Patton might be gone. And the opportunity — whatever it was — would be lost.

An airplane, then. Maybe, just maybe, a lone plane could carry her to North Africa without attracting the attention of all the warring powers.

Grace’s brow darkened. If the warring powers weren’t going to be thrilled about this, Beatrice was going to be even less thrilled — not to mention Giselle and Madame Fourchette. And somewhere, when the news of Grace’s disappearance reached Father, he was going to blow a gasket — if James Cahill even remembered the family he’d left stranded in Monte Carlo.

Well, there was simply nothing for it. Cahills had been changing the world for centuries. If there was ever a world that needed changing, it was this one.

Grace’s suitcase lay open on the bed, empty but for one item — her passport. The future she was heading into was so completely unknowable that she couldn’t think of a single necessary thing to pack. Fresh clothing? Where would she find a place to change? A toothbrush? Was there running water on a battlefield? In the end, she pocketed the passport and stuffed the suitcase back in her closet. The only thing that seemed fairly certain was that she would be running for her life. Luggage would only slow her down.

What was really required here was money. Cash opened doors and greased palms and hired planes. There was plenty of it in Father’s safe, but only he had the combination. This was not for lack of trying. Many times Grace had scoured the house for a hint of what the numbers might be. Not that she intended to steal from her father. She’d always had a sense that access to the safe might come in handy one day. And, she reflected ruefully, she’d been right.

Stealthily, she crept into her father’s study. She could hear Fiske in the kitchen, demanding a cookie in English, and Giselle arguing with him in French. Grace smiled in spite of herself. As if a baby would understand or even care. She had little doubt that her brother would win his cookie. He rarely took no for an answer. She felt a sharp pang at the sound of his shrill voice. She was about to abandon him — just as Father had abandoned them. She had every intention of coming back, but the mission she had planned for herself was fraught with so many risks that she couldn’t wrap her mind around them all. And those were just the hazards she could foresee.

She was not like Beatrice, the eternal doom-crier. But she had to admit to herself the very real possibility that this journey might turn out to be a one-way trip.

 If I die, who will be here to love Fiske?

She shook herself and returned to business. The safe.

She already knew the first number to try — 39. Whatever it meant, it was central to the legacy of the Cahill family. She was convinced that her father would use Cahill references in his combination. Mozart’s birthday, perhaps — James was a huge admirer of their composer cousin. January 27.

Holding her breath, she twisted the dial. 39-1-27.

 Locked.

Abraham Lincoln, then. February 12 — 39-2-12.

 Locked.

She tried Howard Carter — May 9; Emperor Puyi of China — February 7; and the Grand Duchess Anastasia — June 18. By now, beads of perspiration stood out on her brow. It was sinking in that there were hundreds of famous relatives — and dozens of numbers associated with each of them — dating back to the fire that destroyed Gideon Cahill’s lab in 1507.

 Wait a minute! 1507! 15-07!

She turned the knob — 39-15-7. Fingers trembling, she reached for the handle.

Her face fell. Locked.

She’d known from the start that she might fail in this adventure.

 But not before I get out of Monte Carlo! Not before I even get out of the house!

All at once, her downcast features rearranged themselves into a quizzical expression. She tried the numbers again, this time in a different order.

15-7-39.

There was a metallic click, and she swung the heavy safe door open.

 Wow.

It was more money than she’d expected — a lot more. Stacks of bills bound with rubber bands — French francs, British pounds, Italian lire, German marks, and American dollars. There was even a canvas bag of gold coins. She took a leather briefcase with her father’s initials and stuffed in as much as would fit. In normal times, it would have been enough to take her to the North Pole and back. But this was war. Everything was different now.

“I’m going out for some air,” she called to whoever might be listening. The lump in her throat as the door shut behind her was larger than she’d anticipated. This wasn’t home, really. But it was the last place Mother had lived, and every memory was precious.

She got on her bicycle and started off down the shore road. It would have been comical if the situation hadn’t been so grave — pedaling off to war with a fortune balanced in the wire basket of your bike. She had an insane desire to ring the bell.

Their villa was not far from the airfield because nothing was far from anything else in a country that was smaller than one square mile. Monaco was a perfect jewel, with its cathedral and medieval palace perched on a rocky promontory on the coast. She had always considered it the loveliest place on earth. Now it would always be the place where Mother had died. Its beauty no longer existed for Grace. Its spectacular winding hills merely made cycling a chore.

She pedaled up to the airfield and left her bike leaning against a wall. The building was tiny, with a doctor’s office-style waiting room and a single counter. “Excuse me, monsieur,” she told the clerk, placing her open passport on the desk. “I wish to arrange transportation.”

The man looked down his long nose at her. “Where is your father, mademoiselle?”

Grace was not intimidated. “I am the one traveling, not my father. I need to get to Casablanca, in North Africa.”

The man’s shock turned to laughter. “Casablanca? Even as we speak, mademoiselle, Casablanca is under attack! It is no place for a little girl!”

“Luckily, I’m not a little girl,” Grace said coldly.

“Even so! There are no flights to Casablanca! No one is flying there except for the purpose of dropping bombs!”

“I realize that,” Grace conceded. “I’m here to charter a plane.”

“Presuming you are able to find a pilot reckless enough to go,” the clerk blustered, “he would demand a king’s ransom to risk his aircraft and his very life in this way.”

In answer, Grace set the briefcase on the desk and flipped it open.

The man’s jaw dropped so low that she half expected him to knock his teeth loose against the counter. “I will consult with the pilots!” he exclaimed in a strangled voice, and disappeared through a swinging door into a back room.

Grace snapped the case shut, suddenly self-conscious. She might not be a “little girl,” but she was a ripe target for robbery.

The clerk returned after barely a minute. “It is as I told you, mademoiselle. No one is willing to take you to Casablanca.”

Grace tapped the case. “There’s gold in here as well.”

He favored her with a full body shrug that was very French. “A dead man would have no opportunity to spend it. I am sorry, but this disappointment is probably prolonging your life.”

She withdrew, feet dragging, the bag heavier than ever. Briefly, she considered using the money to buy a plane and trying to fly herself, but quickly abandoned the idea. She did not yet have her pilot’s license, and her navigation skills were as likely to take her to Sweden as North Africa.

A feeling of helplessness took hold in her gut. If no pilot would fly her, what could she do? She couldn’t pogo-stick across the Mediterranean!

She was climbing back on her bike when a low, heavily accented voice startled her.

“Why you want to go there?”

The dark, unshaven man who stood before Grace was built like a stone toad — short, with no neck and a torso so hulking it didn’t seem likely that he’d fit in a cockpit. Part of the problem might have been his voluminous ratty fur coat that looked like it had come from a woolly mammoth.

“Are you a pilot?” she asked.

“Is war in Casablanca,” he persisted. “Why you want to go?”

“That’s my business,” she told him sharply.

“My business is staying alive,” he told her evenly. “If I have brains, I don’t go there. If I have money, I don’t go there.”

“And do you have those things?” Grace asked, trying to hide her eagerness.

“It will cost much,” he warned.

“I’ll pay you ten thousand American dollars.”

The man’s bushy eyebrows jumped, but his voice remained impassive. “Twenty — in advance.”

“All right. Twenty — when we get there.”

“How I know you have this money?” he demanded.

Grace shrugged. “How do I know you have a plane?”

He grunted. “Come back — midnight. Wear black. You bring money. I bring plane. If anybody asks, you never spoke to Drago.”

Grace had the audacity to fly into a war zone in search of an invading general, but she lacked the courage to return to the villa. Once reunited with baby Fiske — and even disagreeable Beatrice — she was afraid she might never leave again.

At a store by the palace, she bought black slacks, a black blouse, black boots, and a black leather coat. The clothing was expensive, designed for hobnobbing with high society, not for a desperate night flight. Still, money was the one thing she had plenty of — as opposed to wisdom, or experience, or even a clear plan of what she was going to do once she got to Casablanca. If this was her first test as a Cahill, she was pretty sure she was failing miserably.

She toyed with the idea of renting a locker for her old clothes but ended up throwing them in the trash. This was no game. Operation Torch was an actual shooting battle. There was a very real chance that she might not survive this adventure. But even if she did somehow come through it all, she had a sense that she’d never be the same again. The Grace Cahill who wore frilly flower-print dresses and adored romantic novels and movies was gone forever.

As night fell, her thoughts returned to her family. Were they anxious about her back at the villa? Probably. She could only hope that Beatrice would hold off calling the police until Grace was airborne.

11:55. She pushed her bicycle into a drainage ditch, hefted the briefcase, and walked out onto the deserted airfield. All was dark except for a dim light coming from one low hangar. She made for it, heart pounding in her ears.

As she drew closer, the biplane came into focus — hulking, dilapidated, patched with tape and fabric. Crudely painted on the fuselage was a name: OLGA.

A gasp of dismay escaped Grace.