She drew on the source of energy that still filled her to the brim and murmured the incantation she knew so well, the same incantation that had allowed her to gain access to Professor Saffyn’s drawers what felt like so long ago already. Except that this time, nothing happened.

The spell flared, pushed against air, finding nothing to touch, nothing to fight, and faded uselessly.

Lautric frowned at Fern’s expression. “What is it?”

“It’s not working.”

“Your incantation?”

Fern shook her head, eyes fixed on the door. “No, not my incantation. The door. It’s as though… as though there isn’t a lock at all.”

“Could the door be walled up from the inside?”

Fern turned slowly away, thinking back on what Josefa had said about her apartment door and the way her key had failed to work.

“Either way,” she said, “it won’t open. There’s no way in. Whatever this looks like, whatever it is—it’s not a door.”

Lautric said nothing. He gazed up at the tower; the muscles in his jaws twitched. What was he thinking? Did he know who it was they heard? Did he know more than he was letting on?

“What should we do?” he said in a dull murmur.

“Whatcanwe do?“ Fern said, throat tight.

He was silent. They both were, staring up at the tower, the ghost of the scream stretching between them.

“We’d better get back,” he said finally. “In case Sentinels are on the way.”

He turned his back on the tower and set off through the Arboretum. Fern cast the ancient tower one more look. The black column of stone jutted out towards the sky, blocking out the moonlight.

They might not have been able to gain access to it, but she knew something Lautric didn’t: that the passageways branched out towards each tower like subterranean spider’s legs. Fern was already growing more familiar with the passageways, expanding on her map.

If there was a way in, she would find it. If Josefa was in there, Fernwouldsave her.

Fern watched Lautric asthey made their way back to the Mage Tower. His limp, his shoulders slumped with exhaustion, his heavy backpack and the cloth-bound cylindrical object slung through it, his pale neck and shock of choppy black hair. Though she was silent, a thousand questions crowded on her tongue.

Where had he been? Who had injured his face? What had poisoned him? What did he know about the events of the Arboretum? About the other events? Josefa, the break-in?

He’d told her he was distracted during the first assignment; he’d been telling the truth. She’d been too busy defending herself to think properly on it—this distraction of his. But now, her mind focused on the question. What was it that was distracting Lautric enough that he was risking failure here, in Carthane, when his family had coveted a way in for so long?

And perhaps that was the most important question of all.Whyhad he come to Carthane?

They passed the Sentinels on the way back into the Mage Tower, and Fern’s steps faltered, remembering the one in Saffyn’s office. Had it seen her, and would these Sentinels know her?

But the two shadowy silhouettes made no movements; their bodies stood motionless in their dark alcoves like corpses propped up in open coffins. Whether they were asleep or unconcerned by Fern’s and Lautric’s presence, it was difficult to tell. Lautric held the heavy door open, letting Fern pass through.

Inside, he followed her past the shadowy atrium, where two pale busts faced each other from across the chessboard tiles of the floor, then up the broad spiral staircase. Lautric was the first to break the ponderous silence that stretched between them.

“Who do you think it was?”

Fern stopped in her tracks in the darkness of the staircase and stared up at him. “Do you have no idea?”

He turned with a frown. The light from the corridor lamps above softly framed his face; the combination of his handsome features and tired eyes always lent his expressions a disconcerting sincerity. It made it difficult for Fern to remember how dangerous his house was, how unwise it would be to trust him when she had a threat bearing his house symbols in her pocket.

“I’m not sure what I think or believe anymore,” he breathed.

There was a tone in his voice she had not expected: exhaustion mingled with despair. It had been a long and tiring night for both of them. Fern would never trust the Lautric House, and she still disliked being partnered with him for their assignment, but she could not deny that, for this night at least, she and Léo Lautric had become allies.

“I think something happened to Josefa Novak.”