Nikki Heat’s footsteps echoed back at her off the concrete tunnel as she ran. The passage was wide and high, big enough to truck in exhibits for both museums in the complex: the American Museum of Natural History and the Rose Center for Earth and Space, aka the planetarium. The orange cast of sodium-vapor lamps gave good visibility, but she couldn’t see ahead around the curve of the wall. She also didn’t pick up any other footfalls, and coming around the bend, she saw why not.

The tunnel came to a dead end at a loading dock and nobody was there. She bounded up the steps to the landing, from which a pair of doors fed off—one to the natural history museum on the right, the other to the planetarium on her left. She made a Zen choice and hit the push bar to the natural history door. It was locked. To hell with instinct; she went for the process of elimination. The door to the planetarium service bay popped open. She drew her gun and went in.

Heat entered in the Weaver stance, keeping her back to a line of crates. Her academy trainer had drilled her to use the more square and sturdy Isosceles, but in tight quarters with lots of pivoting, she made her own call and assumed the pose that let her flow and present less target area. She cleared the room quickly, startled only once by an Apollo space suit dangling from an old display. In the far corner she found an internal staircase. As she approached, somebody upstairs threw a door open against a wall. Before it slammed shut, Heat was climbing steps two at a time.