A Garonin soldier appeared at the corridor entrance, stooping to squeeze his frame into the confined space. Jonas hesitated, looking up at the eight-foot-tall figure hunched under the low ceiling. But not for long. With a cry, he swung his sword round and up. The blade sheared through armour at the waist. The Garonin howled in agony and fell back.

Densyr made the end of the corridor and cast his Defence spell down it. Two more Garonin stood there. White tears played over the blue-washed barrier. Densyr could feel every impact through his arms. He clung on to the casting, finding it hard to concentrate.

‘What’s going on?’ he asked himself.

By him, Jonas was staring at the blood on his sword. He was shivering.

‘I killed someone,’ he said, his voice tiny.

‘And though I shouldn’t say it, your father would have been proud of you. Just check your moves with me first next time, eh?’

The answer to Densyr’s first question became obvious. The walls all around them and throughout the catacombs glowed deep blue and trembled. Densyr pushed hard at his casting, forcing the Garonin back along the corridor.

‘Time to leave. And quickly.’

There was beauty in the way it all folded back, thought Dystran. A certain symmetry of which Septern himself would have been proud. The lines of the ward grid had gathered together when he had let go the entry point between Heart and casting. The place where he should have set his mind to keep the opposing forces at bay was now empty. There was more he could do, however, and do it he did.

Dystran imagined himself humming as he did his work. His mother used to hum when she was cooking so it seemed the right thing to be doing. Dystran did not want to let the small chance that the energies within the grid would dissipate come to fruition. So he directed the mana flow back along the grid lines, using his failing mind to force them into the shape of a rope with individual fibres spiralling together.

And when that was thick enough, for his own amusement he gave the shape of this focused mana an arrowhead. Feedback. The most terrifying force any casting mage would ever face. But at this moment, Dystran’s last on this Earth, it was simply stupendous in its simplicity and its power.

The arrowhead slammed into the gentle pulsing hourglass of the Heart’s mana. There really could be only one outcome. He hoped Densyr escaped it. That would somehow be just.

For Dystran the world turned a fiery blue and then to utter dark.

Densyr gathered every ounce of strength in his mind and pushed. The Garonin were shoved straight into the hub room and flattened against the wall to one side of the stairway. Surely there were many hundreds more enemy up the stairs but that was a chance they’d have to take.

Densyr held the spell a few moments more.

‘Got to ask you to do something, Jonas,’ he said.

‘I know,’ said Jonas. ‘I’ll take left.’

‘Good lad. Don’t think about it. Only consider what they have forced your father to do. Don’t let them take any more of your family.’

Jonas nodded, a grim expression on his young face. The sight of it angered Densyr more than anything he had seen these past days. He gave the Ilkar’s Defence another shove, batting the heads of the Garonin against the wall one more time.

‘Dropping on three,’ he said. ‘One, two . . . three! Defence down.’

The two of them rushed the stunned Garonin. Densyr dragged a dagger from his boot sheath, reached up and rammed it into the neck of his target. Beside him, Jonas gave a wavering call and stabbed his man through the stomach. His blade ran straight through and screeched against the wall.

‘And now it’s time to run.’

Densyr ran for the stairs up to the ruined tower complex. He had not got two steps before he felt the air being sucked out of his lungs. A wind howled down the stairs, a mana gale that blasted through his mind. Behind him Sol’s family couldn’t feel it at all. He screamed and clamped his hands to the sides of his head, dropping to his knees and tumbling back.

He felt hands about him, trying to help him. All around them the blue in the walls had faded to a crisp white and frost bulged out, thick and grabbing. Ice fingers probed into millennia-old stone. The catacombs gave a death rattle. A complete silence fell.

‘What’s happening?’ asked Diera.

‘The Heart is about to stop beating,’ said Densyr.

There were footsteps on the stairs. Densyr swore. Hirad screeched and clutched hard at Diera’s neck. Four Garonin pounded into the hub room. Densyr wasn’t ready. He had no spell prepared. His head was thumping as loud as the enemy boots. Jonas rushed in, yelling at them to leave his mother alone. A Garonin arm came round. The back of the soldier’s hand clattered into Jonas’s chest, sending him sprawling.

Diera and Hirad both shrieked Jonas’s name. Garonin weapons trained on Densyr. He bowed his head and closed his eyes. From his left two shadows whipped by. He heard a Garonin shout. There was a howl and then the crunchy of fang on flesh and bone. A weapon was fired, dust and stone fell from the ceiling. Densyr dared to look.

Both wolves had attacked from a side passageway. Two Garonin were down. The other two trying to beat the wolves back. Jonas stormed past him and hacked his sword into an exposed back. Densyr, impelled to action, freed his dagger again. He paced forward. The one free Garonin reared back, a wolf snarling and snapping in his arms. The soldier roared with the effort.

Densyr jammed his dagger blade hard into the back of the Garonin’s left thigh and kicked into the back of his knee. The Garonin pitched forward. The wolf spun in his grip. Claws and fangs lashed in. Before long, the enemy had ceased his struggle. Blood slicked across the hub room floor.

Densyr, breathing heavily, nodded his thanks at Jonas. He wiped his dagger on his trousers and sheathed it. A bass rumble rippled out from the centre of the catacombs. The hub room shook. Areas of the plaster ceiling fell in. The walls heaved. Fissures appeared within, shattering ice. The wind began to howl again but this time all could hear it.

‘Run!’ yelled Densyr.

He sprinted back to the stairs, trying to ignore the pounding in his head. Jonas was by his side, bloodied sword still held in one hand. They ran out into the devastation that had once been the tower complex. Nothing was left now but treacherous ruins. Ruins filled with Garonin. A hundred eyes turned on them as they fled the top of the stairs and were forced to stop by the piles of stone blocking their path. Fifty weapons were brought to bear. The wolves placed themselves in front of Hirad and Jonas, barking out warnings. Lips curled back from teeth and hackles rose.

‘To me,’ shouted Densyr. ‘Huddle close.’

There was a growing whine in the air, replacing the silence. Densyr cast quickly and efficiently, trying not to think about the fact that it would be his last casting as a true mage of Xetesk. He had a choice to make. To deflect the Garonin weapons was one option. He chose a second. Densyr stared at the nearest Garonin as the soldier’s hand rested on the trigger of his weapon.

‘I’d duck if I were you,’ he said.

The Heart of Xetesk exploded. The speed of the shock wave was incredible. The ground rippled underfoot, upsetting every Garonin, pitching them from their feet. It was followed by a series of detonations from deep within the catacombs. Densyr’s Orsyn’s Cocoon covered the four of them above and below, a seamless bubble of mana that he would cling on to for as long as his mind would let him.

From the centre of the catacombs the ground heaved in expanding concentric circles. Cracks were torn and blue fire lashed out, sending shards of stonework out in lethal clouds. Garonin, struggling to their feet, were cut to shreds in their tens and dozens. The ripple detonations thundered beneath Densyr and his charges. They were cast up eight or ten feet and dumped back down.