Isabelle ticked off marks in her journal and calculated timing and position of the next escort. “We’re already on our best wind. At our current speed we have just enough time to reach the wind wall before the next escort window. We have to be at the point of contact, moving in the right direction at the right speed when it does, or we might as well scuttle ourselves.”

Similce squinted at the towering squall. “How much room for error?”

“A minute. Two at the outside.”

Similce’s expression grew grim. “That’s no time at all.”

“It’s worse than that,” Isabelle said. “We have to hit it at speed to slot into its vortex.”

Similce faced the storm wall, an endless smear of wind that sounded like a roaring waterfall even at this distance. “How can you even tell where it’s going to be?”

“Trigonometry,” Isabelle said. She gathered her gear and led her lieutenant into the chartroom, and adjusted the orrery, increasing the pressure and decreasing the scale until only the two charted objects closest to the ship were visible. The Saint Asne was the bright mote in the center.

“This one is the beacon we dropped on Rüul, and that one is the Conquest,” Isabelle said, and thanked Jean-Claude for getting the shard to her. She spread a large sheet of rice paper across the orrery and ruled in those points. Then she pulled out her trigonometry tables, did some quick calculations, and ruled in a fourth point.

“That’s our entry point,” she said. “As long as we can keep these two points of the triangle on our beacons, we know exactly where it’s going to be. I just need you to put us at that point in exactly”—Isabelle checked her timepiece—“one hour and five minutes.”

“Ask for the moons while you’re at it,” Similce grumbled.

“That’s tomorrow,” Isabelle said.

Similce saluted and stepped outside. “Beat to quarters and clear for action!”

The crew made the ship ready for battle. They brought up lumber from stores and hammered together an extra layer of armor for the port side, where the Bittergale would hit them. Bitterlich made sure his marines got as fed and rested as possible. Every cannon aboard was checked and rechecked, every loose thing doubly secured.

Through it all, Isabelle stood fast, refining her calculations. The Saint Asne would have to pull up alongside a runner at the very tip of its turn, running the wind at full sail, and even that didn’t guarantee they’d have enough momentum to stick in the vortex hole.

The hour crept by and the Solar skulked along the southern horizon like a fox scuttling across a road. Isabelle tracked the Saint Asne in the orrery as it drew closer and closer to the point of influx, checking her timepiece and counting down. They had nothing to spare.