‘The alien is a spiritual demon—a sentry, posted to guard our father. The silicon skin gives it form and substance in the physical dimension. Its most deadly feature is its claws, which release a fast-acting toxin. Our Hunahpu genetics can fight the poison in small doses, but anything more than a severe scratch would be fatal.’

‘Lovely.’

A brilliant explosion of emerald green light ignites across the horizon.

‘Computer, pause.’

The on-screen image freezes as the two warriors sprint toward the alabaster-goo tree.

‘We’ve just entered the nexus. What follows will play at less than 3 percent of its actual speed.’

‘Three percent? I can’t move that fast.’

Jacob flashes a grin. ‘Not yet. Computer, resume play at nexus speed.’

The scene continues, frame by grainy frame. The twin in white is almost flying around the lake, his feet barely touching the shoreline. He reaches the tree at the same time as the demon sentry. Drawing what appears to be a sword, Jacob lashes out at the frightening creature, keeping it at bay.

With each stroke the blade glows a deeper shade of blue.

‘Lasers and guns do not work in the nexus. The sword is made of a nanofabricated alloy steel. With each movement, the macromolecular motors within the blade expand and heat the edge, threatening to cut through the demon sentry’s silicon outer skin. The blood bleeds blue without hemoglobin, because there is no oxygen on Xibalba, only CO2.’

The warrior in white is a whirlwind of movement, slashing and parrying, stabbing and retreating, barely able to keep out of the larger sentry’s superior reach.

Immanuel shakes his head. ‘How can you keep that up? I would have collapsed long ago.’

‘Training. Now watch carefully.’

The black-clad warrior representing Immanuel has reached the tree. As he attempts to free the drone representing their father, the demon sentry suddenly lunges toward the trunk, attempting to strike the virtual-reality Immanuel with its left claw.

But Jacob is too quick. Having clearly anticipated the move, he dives forward, slamming his now-flaming sword down and through the alien’s right arm, severing it at the elbow joint—

—as the black-clad warrior lashes outward with his own sword, decapitating the stunned sentry with one powerful blow.

The monstrous skull thuds against the rocky surface, its headless body following suit.

‘Yes!’ Manny is on his feet, barely able to catch his breath. ‘We won … right?’

Jacob shakes his head. Points.

The drone representing Michael Gabriel is lying against the simmering remains of the calabash tree, blue blood streaming profusely from his abdomen.

‘Computer, rewind six hundred frames and pause.’

The image returns to the demon sentry’s lunge toward the tree. ‘Watch closely. His left claw is the decoy. Ignore it and focus on the right. Computer, resume at 1 percent nexus speed.’