‘In order to reach the throne at its summit, we must ascend it in the sacred order of the holy tree, which, fortunately for us, was laid out in the Kabbalah.’

Mendoza pulled out a diagram of the castle and also a drawing of the Kabbalistic Tree of Life with a set of arrows drawn on it.

Mendoza said, ‘The Kabbalistic Tree of Life represents the sacred path from humanity/Earth at the bottom—called Malkuth—to divinity/Heaven at the top—known as Keter.

‘As the lowest rung of the Tree of Life, Malkuth is all things physical. It is also the barrier between the realm of life and the underworld, the realm of the Tree of Death. Keter is the opposite. It literally means crown. It is where a man becomes a god.

‘To get from the bottom to the top, you must follow the path in the correct order. Some believe this is a spiritual path, one of enlightenment. But it isn’t. It’s all about scaling this castle, here, in the Supreme Labyrinth, to get to the Throne of the Tree of Life. Look at this diagram of the castle now . . . and see how the path fits the layout of its window-platforms perfectly.’

The cardinal quickly scribbled the arrows from the picture of the Tree of Life onto the drawing of the castle:

Sphinx’s eyes lit up as he saw the connection.

‘A transformation from humanity to divinity.’ He smiled. ‘From man to emperor. Let’s move!’

The first archway stood before them. Three sets of upward-leading stair-bridges sprang away from its roof in three different directions.

The archway was a large dark cube-shaped structure decorated with black horn-like protrusions and fearsome-looking statuary. Short stairways led to its roof and it had a broad well in its floor.

Obeying the arrows on the diagram and invigorated at being so close to success, Sphinx and his team dashed up the right-hand set of stairs leading up from that first archway to the next one high above it.

And so Sphinx ascended the interior of the castle swiftly, finding order in its otherwise baffling maze of crisscrossing internal stairways.

He was three-quarters of the way up when Ezekiel and his Omega monks arrived at the bottom of the castle.

The Omega monks fanned out to positions both inside and outside the castle, firing pistols and sniper rifles up at Sphinx, Mendoza and Jaeger Sechs, but it was to no avail. The stairways and landings blocked their shots and Sphinx was simply too far ahead.

Then, at last, Sphinx ascended the final stairway and he burst out into sunlight, arriving at the summit of the castle, high above the circular city-maze.

The view took his breath away.