Say it! Go ahead.

But try as she might, the name Cahill stuck in her throat. Her training was bone deep.

As sunlight poked through the clouds and into the room, a tiny windmill of black-and-white sails began to turn on a table. These knocked a pebble down a chute, striking a hook that released a weighted pulley, which in turn raised a small spring-loaded hammer. The hammer then struck a brass gong, signifying the end of alchemy class.

Soon the distant tune would sound — Mother summoning her, expecting help in the apothecary. Leaving behind the sleepers, Madeleine raced outside. She sped down a sloping path through heather and scrub. A low bank of clouds swept over the moor, casting the village of Scáth below in gray-green mist.

Madeleine looked up to the soft-ceilinged sky as she ran. She thought of her father, a man she’d never met. Mother claimed he had been the greatest alchemist and an even better father. She hoped that wherever he was, he was looking down and seeing the results of her alchemy training. Even more, she hoped he was proud.

In a moment, her shoes hit the cobblestones of town. She wove through winding alleys that echoed with the distant sound of a tin flute, piercing and sweet. This was Mother playing a tune called “Bhaile Anois,” which meant home now. It was composed by Father and had become the traditional Cahill family song of summoning. As she ran, Madeleine waved to the pink-faced baker and soot-blackened chimney sweep, the burly butcher and weary lamplighter.

She dashed around the corner of Front Street. Carriages groaned up the hill, passing an old beggar woman who slept in the shadow of an abandoned stable. Ahead, the street descended toward the lake, where it flattened and followed the gentle curve of the bank. At the bottom of the hill stood O. Babbitt & Daughter Apothecary.

Madeleine slowed. Before the shop, a crowd of people had gathered in the street. A group of men was pounding on the front door. They were dressed in hooded capes of purple and black. Behind them stood a massive wooden dray cart tethered to pack horses. On the cart, three men lay moaning and half dead. Shackled to the cart’s frame, his clothes ripped and face covered in blood, was Professor Xenophilus.

Madeleine stopped.

The old man slowly turned his gaze up the hill. His deadened eyes settled on her. He gestured feebly with an arm that hung at an odd, unnatural angle. Run away, his body language was saying.

One of the caped men spun toward Xenophilus, smacking his head with an open fist. The teacher’s knees crumpled and he fell to the cobblestones. “Old fool,” the man bellowed, “are ye sure there be Cahills here?”

Madeleine stumbled backward at the sound of the name she’d only ever heard uttered by her mother.

How did they know? How could Xenophilus —?

 Last week. Under her teacher’s observation she’d sampled an earlier version of the formula. Just a bit. Upon awakening, he’d scolded her about proper dosage. Too strong, and the potion induced coma! Ah, but too weak, and the recipient was half awake, unable to stop from saying his or her innermost thoughts!

The look on his face had startled Madeleine. His usual jovial, patient expression had changed. He seemed confused, as if seeing her for the first time.

 I must have told him that day, she thought. Under the earlier, weaker formula, I must have revealed my name. It made sense — her father was so often on her mind. Surely Xenophilus would have recognized the name of such a famous alchemist.

And now the secret had been beaten out of him — because of me, she thought. But by whom? Who were these people?

A loud crack rang out. The men were using a wooden ram now, and the apothecary door was about to give.

“We know you’re in there, woman!” a voice shouted.

“Mother!” Madeleine screamed, running down the hill.

As she passed the stable, the beggar woman moved. Springing to her feet, she grasped Madeleine by the neck and dragged her into the shadows.

Over the years, Madeleine’s training had included ancient fighting techniques to subdue men of great size and strength — but nothing for homeless old women in alleyways. “Let go, you old buzzard!” she cried, struggling against an iron grip.

As she whirled and lashed, the old lady countered every move. “Good grief, will you stop making such a racket!” she finally cried out. “They’ll hear us!”

Madeleine froze in mid struggle. She fell to the ground and looked up into her adversary’s face. “Mother?”

Olivia Cahill pulled back her woolen hood. “This old buzzard just saved your life,” she said.

“I’m so sorry!” Madeleine protested.

Olivia put a gentle finger on her daughter’s lips. “We must be quiet, and quick—”

Below them a voice boomed, loud and angry. “Open in the name of Lord Vesper!”

 Vesper.

The name hit Madeleine like a shift in air pressure. As if the entire world were converging on her, pressing against her heart and brain. All her life, Damien Vesper had seemed more bogeyman than real — the shadow in the closet, the monster under the bed. He will find us or die trying, Mother had said. And he will stop at nothing to get the secrets of the 39 Clues.

Some monsters, Olivia had warned, were real. And to ward off this one, all Madeleine had needed to do was keep her mouth shut over the years.

One simple request, and she had failed.

“I-it’s my f-f-fault, Mother!” Her stammer had returned with a vengeance. Madeleine felt the weight of her own betrayal. She had not only put Xenophilus’s life in peril but exposed her and Olivia to their nemesis.

“Hush, darling daughter. It was only a matter of time. They have been trying for nearly two decades.” Olivia’s voice was parched. Reaching down into the folds of her ragged dress, she pulled out a small leather box. “Consider how lucky we are that we avoided them long enough for you to be prepared.”

 Prepared?

Madeleine felt anything but. Yes, for years she’d been learning the secrets of the 39 Clues, undergoing physical and mental training, tracking rumors about her siblings. Still, it had all seemed so … abstract. She had been born after the explosion that killed her father. She’d never met her brothers and sisters. Somehow, the Cahill saga seemed more legend than real, like the tale of the monster Vesper.

Another boom, like a cannon shot, echoed from down below.

Olivia flinched. “I had such hopes — we would outlast him, you would never face him in your lifetime…. But so be it. We will act quickly and decisively. Take this box — and please, recite for me your promises!”

Madeleine grabbed the box with shaky fingers. Mother had called this the Endgame Strategy. She hated the name. “B-b-but you will come, too, won’t you?”

“He doesn’t know you exist — so you must go forth alone, as planned. Your brothers and sisters are full of anger. They blame one another for your father’s death. We will need to work on them. Be careful, and remember: Smartest always beats strongest. I will destroy what little is left of your father’s work, and then I shall follow. Now, please, let me hear the promises. ...”

Madeleine’s mind raced, trying to remember. Father had a ring. It was an ugly thing, but it contained secrets. Secrets Olivia had never explained. Keep Father’s ring safe. That was Number One. Number Two was —

Another sickening crack rent the air. A volley of triumphant voices.

The men were in.

Olivia stiffened. “I will go in the back way and hope they do not find the hidden door. Go!”

“But — the promises —” Madeleine protested.

“Just remember them, Madeleine, and whatever you do, stay alive. And one more thing. Do not look back.” Tears in her eyes, Olivia cupped her daughter’s face and planted a kiss on her cheek. “And may God go with you always!”

Before Madeleine could say another word, her mother was gone. Into the shadows and through a secret back door to the apothecary.

Madeleine stepped toward the door in pursuit. Her ear suddenly pinged with a high-pitched whoosh. She felt a trickle of blood down her neck. An arrow.

A finger’s breadth to the left and it would have split her brain.

“You! Come out of the shadow!” a voice called up from below.

 He doesn’t know you exist.

There was work to be done. The Endgame was afoot.

Madeleine turned her back to the voice. Vesper could not see her face. She began to run, away from the stable, up the hill. She heard shouts and felt the zing of arrows all around her.

She heard another voice shout from below: “You imbecile, it’s a lassie — too young for the wife! Spare my lord’s arrows and help prepare the powder!”

Madeleine darted around the next corner. She knelt by the brick wall of the bakery and caught her breath. Blood had pooled in the well of her collarbone. Carefully, she touched the wound, but it seemed already to be healing.

 The powder. What had he meant by —?

A sudden explosion rocked the stones beneath her feet. Inside the bakery, shock waves caused rolls and bread loaves to clatter to the floor.

As Madeleine scrambled to look around the corner, she heard a shriek that rose to an unearthly pitch and then ended in a guttural rattle.

The apothecary and the stable collapsed in a heap of brick and flames, with Olivia Cahill inside.

Madeleine could do nothing but scream.

 1. Keep the ring safe.

 2. Never let anyone abuse the power of the 39 Clues.

 3. Unite the Cahills when the time is right.

The promises were stamped in Madeleine’s brain. She hadn’t recited them as her mother requested, and now they would not let her go. She drew her cloak against the bitter morning wind. Hidden behind a thick copse, she brushed away tears and glanced down through tangled, thorny branches.

In the village cemetery, a priest intoned prayers over a freshly dug grave.

Local merchants, arm in arm, wept for one of their own. The neighbors, many who owed their lives to Olivia’s healing skills, sobbed openly. Madeleine’s friends clutched one another. So did her fellow apprentices, long recovered from the sleeping potion.

 I am so, so sorry, Mother, she thought. But the unspoken words seemed hollow and pathetic.

She recalled Olivia’s final two requests: Stay alive. Do not look back. Already Madeleine had broken the second one. Perhaps if she hadn’t looked back, she wouldn’t have seen the explosion. And all this would not have hurt so much.

 Is this to be my fate? she thought. To be a promise-breaker? A secret-revealer? A betrayer of the people I love most? A bringer of death?

Madeleine could not stand the hiding. The fakery and failure. The idea that she had trained all her life for … what? What did any of it mean, now that her mother was dead?

She rose on unsteady legs. She would run down the hill, fling herself on the grave. She would beg God to return her mother and take her instead.

But her body went cold at the sight of a man on the edge of the gathering. His eyes were not focused on the service but instead scanned the countryside. He wore vestments of deep velvet and stood before a richly appointed carriage with magnificent horses. His face was lined and sagged with age, but he sported a mane of jet-black hair, save for a serpentine silver streak down the right side. And his expression made it clear he cared nothing for the deceased.