“The merest blink of an eye,” said the Emperor, beneath his breath. He pushed himself away from the pilot’s chair and said, “We worked out a while ago—I say we, but I had little to nothing to do with it—that distance is different down there. The River doesn’t flow through the time and space we’re experiencing right now; the River is—well, it’s a current below us, as in the magma analogy. Distance in the River doesn’t map to distance above. If I drop us into it we can emerge almost immediately across the universe, home. The station, our refuge. We call it the Mithraeum.”

He spread his hands wide: ordinary hands, ordinary fingers, ink-smudged nails. “Look at the ward. What is it?”

You were beginning to note the register of his Teacher voice. This was familiar ground, untouched by magma. The ward undulated in the shadows a little, which was a trick of the light and the blood. You said, “It’s just a ghost ward,” and after a second regretted speaking like a provincial bone witch.

Thankfully Ianthe was even more petulant, and a dyed-in-the-wool flesh magician, as she added: “It’s not even a sophisticated ghost ward. I mean, it’s exquisite, impeccable right down to the coagulation. But I was doing those when I was five.”

“That ghost repellent will keep our ship from shaking apart,” said the Emperor. “That ghost repellent will have every lonesome spirit for kilometres screaming away. For a time.”

“One minute, thirty-three seconds,” said Mercy.

He said, “Give or take.”

The Emperor came to drop on his haunches in front of you and Ianthe, as he had squatted before Mercymorn earlier. It still hurt you in an undefinable way, to see him lowered so: as though he offered a compliance test where you ought to flatten yourself in front of him as low as you could go. The white ring around his pupil was so white. “Your job is simple in the way most very tough things are. I will push us into the River, and I’ll push the ship with us. You’ll have to keep your minds—I can take your physical bodies, but your souls won’t go with them, not without you holding them steady.”

“Physical transference past the liminal boundaries,” you said, and were surprised by the knowledge coming out of you, as though it weren’t your own. “This is deep Fifth spirit magic.”

“And I bless the Fifth House and I bless their long memory,” said the Emperor. “They only go far enough to tempt lost ghosts to them. They stand on the sidelines and wave around bits of meat and anchoring material. But they don’t even approach the shore.”

Ianthe sounded much more like her twin sister when she said, wonderingly: “But if applied universally, this would revolutionise the fleet. We could expend no fuel or effort, travelling instantly. We would be truly unstoppable.”