The gatehouse was one of a pair of massive stone towers that sat on either side of the gate itself. Gisco led a dozen men up a stone staircase; soon they were panting with the exertion. Through slit windows Nelo saw the battle opening out beneath him, a pool of struggling, fighting, dying men before the open gate, and a greater Hatti force outside the wall, pressing to enter. At the top of the tower was a small chamber with glassless windows that looked out at the plain beyond the city, where the fires of the Hatti sparked, as innumerable as the stars in the sky.

Nelo was bewildered by what he saw in this crowded room. On the stone flags stood massive wooden barrels, brimming with what smelled like pitch. Under the command of an army officer two harassed-looking slaves were using buckets to transfer this sticky slop to a smaller container set in the middle of the room. This container was connected to what looked like a two-handled pump, a lever fixed over a single pivot; Nelo had seen similar gadgets used to clear minor floods in Northland. And from the container ran a kind of hose, with its nozzle dangling out of the window over the Rus and Scand and their foe.

Gisco nodded to the officer in command. ‘Here’s the muscle you asked for, Sili.’

‘You took your time!’

Gisco hastily dumped his helmet and weapons. ‘Get these slaves out of the way. You two!’ He pointed to Suniatus and another man. ‘Work this pump. See?’ He grabbed the handle and, with an effort, raised and lowered it. Nelo heard the pitch gurgle in the hose. ‘And you—’ he picked two more, ‘—get the hose. Hold it out of that window so you can get the stuff all over the Hatti and their Rus attack dogs. Understand?’

‘No, Sergeant.’

‘Just do it. The rest of you stand by. Watch that door, the stairs – don’t let anybody in until this is over. Got that? And be ready to replace the others at the pumps and the hose. And you, Northlander. Watch. Listen. Draw. Show your Roman master how clever we Carthaginians are.’

The man Sili muttered, ‘Or at least the Syrians from whom we long ago stole this trick.’

‘Shut up, Sili. Just have the wick lit and ready. All set, lads? Get pumping. Hold up that hose. Hold it up!’

Soon black liquid was squirting fitfully out of the hose. Nelo saw it rain down on Carthaginians and the Hatti and their colleagues alike. It was just mucky, oily sludge, and none of the fighters even looked up from the work of slaughter as it fell on them.

But Gisco called down in his own tongue, ‘Fall back! Down there – fall back!’ To the blank astonishment of the Hatti, the Carthaginian soldiers broke and ran, as if leaving the way into the city clear.