“She doesn’t like being reined in,” Stone said. “So—”

He opened up the throttle and the plane surged forward. Sunlight gleamed from the carapace around York, and the Earth curved away beneath her, brilliantly lit.

“Slow roll,” Stone said.

The Earth started to tilt, sideways. It wasn’t as if she was rolling at all; York felt only a slight increase in the acceleration pushing her into her seat.

The horizon arced around her, tipping up, and the bruised purple of the stratosphere slid beneath the belly of the plane.

Then the plane righted itself, sharply. The roll had taken maybe fifteen seconds.

“Snap roll,” Stone said.

This time the plane twisted over in a second, land and sky and sun rolling around, the light strobing across her lap and hands. Her stomach resisted the roll as if she were suddenly filled with mercury.

After one and a half turns the plane finished upside down. When she looked up, she could see the Gulf of Mexico, set out like a huge map painted across a misty ceiling. Gravity plucked at her — one negative G — and her shoulders strained against the seat harnesses, and her helmeted head bumped against the canopy. The blood pooled in her head, making her feel stuffy, as if she were developing a cold.

“Just like the tilt table, huh, Natalie,” Stone said drily.

He snapped the plane through a fast half roll, righting it; the plane settled onto the level, rocking slightly in the air.

For a second they were still. Stone’s precision and control were remarkable, York thought -

And then Stone threw the plane down on a dipping curve, diving down toward the remote ground; the noise of the jets increased.

“Parabolic curve,” Stone called over the jet noise.

So I should be weightless. She relaxed her arm, and watched her hand drift upward. “My God.” She felt the weightlessness in her gut; it was as if her organs were climbing upward, inside her chest cavity.

“You feeling queasy?”

“A little.” She reached down, checking that she could reach the bag in the pocket on her flight suit leg.

Stone made no signs of taking the plane out of its dive. “Ah, you’ll be fine. If it gets too bad, just watch the instrument panel; don’t look out of the window.”

“Okay, but—”

Her sentence fell apart as Stone threw the plane into a ferocious S-shaped curve. She was turned every which way, and the glowing landscape wheeled around the canopy.

And then he took the plane into a straight dive, accelerating at the Gulf of Mexico. The ocean shone like a steel plate, far in front of her face.

At twenty thousand feet Stone hauled the nose of the plane upward. The jets howled, and the Gs shoved her hard into her seat; her head was pushed into her shoulders, and her vision tunneled, walled by darkness.