This gave Gideon time to stand, to ready her sword and slide her gauntlet home, biting the straps tight with her teeth. It was a relief to know she would never have to tell Camilla that her necromancer had died. She was already fighting as though her heart had exploded.

“Stop it,” said Cytherea. Camilla did not hear her. She drove past the Lyctor’s guard and found her blade trapped in a thicket of spines that had evolved from the offhand spur of bone. The spines, flexing like snakes, began to curl over the guard, past her hand, onto her wrist.

Scarcely missing a beat, she stepped in and headbutted Cytherea in the face. The Lyctor’s head snapped back, but no blood showed. She laughed, thickly, hoarse. Camilla’s body jerked, still pinned by the tangle of bones around her hand. Her other knife fell from slack fingers to clatter on the floor. Her skin seemed to ripple and take on a greyish tinge. She began to wither.

As Gideon sized up the best angle to join the fray, a bleached, skeletal hand emerged from behind Cytherea and grabbed her face. Another hand gripped her sword-arm at the wrist. Over Gideon’s shoulder, the skeleton in the fountain began to stir. Harrowhark stood at the top of the stairs, hands full of white particles, her skull-painted face as hard and merciless as morning: she flung them out before her like she was sowing a field. From each grain of bone a perfectly formed skeleton arose, a huge angular mass jostling and crowding on the stairs, and they poured out in single formation to rush the Lyctor one by one. She went under in a sea of bone.

Camilla hauled herself away from the rushing, grinding ocean of Harrow’s mindless dead, clutching her knives more firmly in her recovering hands—the muscles in her arms were visibly springing back into shape. Gideon advanced, heart in her throat, moving to take Camilla’s place.

“Leave it!” barked her necromancer. “Nav! Here!”

Six more skeletons sprang to her call. They were unstrapping something from Harrow’s back—it was Gideon’s longsword, shining and heavy and sharp. She unbuckled her scabbard and let the black rapier fall—shook her gauntlet off next to it, and gave them both a private prayer of thanksgiving for services rendered—and she caught her sword by the hilt as it fell toward her. She wrapped her hands around its grip and hefted its old familiar weight.

The squirming pile of skeletons exploded outward, and so did the floor. Bricks and tiles and splinters of wood scythed across the atrium like shrapnel. Gideon threw herself behind the fountain, Camilla dived behind an old sofa and Harrow wrapped herself in a hard white cocoon. Skeletons tumbled through the air like morbid rag dolls, bone shrapnel pinging off every surface. Cytherea the First emerged from the clusterfuck, coughing into the back of her hand, looking rumpled but entirely whole.

From the hole emerged one long, overjointed leg, then another. And another. A fretwork of bones, a net, a lace of them—long stingers of teeth, a nesting body, a construct so big that it turned one’s bowels into an icebox. The hulking construct that had killed Isaac Tettares filled the room behind its mistress, stretching itself out and expanding, pulverising a wall and a staircase as it emerged. Its great bone head lolled and loomed above them, masklike, with its hideous moulded lips and squinted-shut eyes.

But now this benighted vision stood before its natural predator, the Reverend Daughter of the Ninth House. As yet more skeletons jerked and clambered upward from their fallen comrades, Gideon got up, dusted herself off, and found Harrow standing in a pool of osseous dust and facing the construct with a hot-eyed, half-delighted anticipation. Without even thinking about it, her body moved to take her rightful place: in front of her necromancer, sword held ready.

“This is the thing that killed Isaac,” said Gideon urgently. The enormous construct was still trying to wriggle one leg free from the floor, which would have been funny if it hadn’t been so terrible.

“Sextus—?”

“Dead.”

Harrow’s mouth briefly ruckled. “A necromancer alone can’t bring that down, Griddle. That’s regenerating bone.”

“I’m not running, Harrow!”

“Of course we’re not running,” said Harrowhark disdainfully. “I said a necromancer alone. I have you. We bring hell.”

“Harrow—Harrow, Dulcinea’s a Lyctor, a real one—”

“Then we’re all dead, Nav, but let’s bring hell first,” said Harrow. Gideon looked over her shoulder at her, and caught the Reverend Daughter’s smile. There was blood sweat coming out of her left ear, but her smile was long and sweet and beautiful. Gideon found herself smiling back so hard her mouth hurt.

Her adept said: “I’ll keep it off you. Nav, show them what the Ninth House does.”

Gideon lifted her sword. The construct worked itself free of its last confines of masonry and rotten wood and heaved before them, flexing itself like a butterfly.

“We do bones, motherfucker,” she said.

Her arms were whole again. Her most beloved and true companion—her plain two-hander, unadorned and perfect—smashed through tendrils and teeth like a jackhammer drill. Stinging flails of bone met her blade and exploded into grey foam as she stood her ground and pummelled them with great, swinging arcs of good cold Ninth House steel.

With Harrow there, suddenly it was easy, and her horror of the monster turned to the ferocious joy of vengeance. Long years of warfare meant that they each knew exactly where the other would stand—every arc of a sword, every jostling scapula. No hole in the other’s defences went unshielded. They had never fought together before, but they had always fought, and they could work in and around each other without a second’s thought.

Gideon pushed for space. She forced a path, step by careful step, toward the centre of the construct. A tentacle lashed out at her leg; she sliced it open on the downswing and danced away from a stiff whip of molars aimed straight at her heart. Behind her, Harrow took it: it trembled into its component parts, then became a dust of teeth, which settled into a glue that stuck wobbling tendrils together so they broke themselves into pieces trying to smash away. What Harrow did not take, Gideon struck down. She struck at spines with the mad fury and sudden belief that if she just hit and hit and hit—accurately enough and hard enough and well enough—she could rewrite time and save Isaac and Jeannemary; save Abigail, save Magnus.

But the size of the thing defied thought, and every strike created shrapnel. Harrow was doing something, shielding her somehow; the air was a hail of sharp particles that ought to have shredded her skin, and yet none of them seemed to reach her. Even so, the white-out of pinging, ricocheting chips made it hard to see her target. From the corner of her eye, she saw Camilla running through a blizzard of teeth and spines and swinging bone lappets with both knives crossed in front of her chest—then she was gone, lost to view.

Gideon ploughed through a veil of flimsy bone shafts. They were under the bulk of the construct now. Six more skeletons sprang to life and formed a perimeter—these were pillars without legs, thrust through the floor, with the big plated arms and bone-wadded shoulders of the construct in the Response room. They grappled great breadths of the construct’s tendrils to themselves, and in the clearing between their backs Harrow flexed her fingers together. She shook finger bones out of her sleeves and slapped the trembling phalanges between her hands like clay. Gideon was busy shearing off questing tentacles that snaked past the skeleton guard and went for her necromancer, catching only a confused glimpse of the slim rosary of knuckles that Harrow was looping around her arm. Then Harrow flung it upward like a whip, and it punched straight through the monster’s midsection, burying itself somewhere deep.