Washington, D.C.“Door!” Kowalski yelled from the rear.Gray skidded to a stop and glanced behind him. Elizabeth Polk held out her lighter and revealed a small doorway, hidden two steps off the dark tunnel. Gray had rushed past it, too focused on the roof, searching for a street exit from the service tunnels.Behind them, calls echoed from the searchers. A single harsh bark rang out as the trackers found their trail again. Gray had crisscrossed among tunnels, trying to lose them, but it proved fruitless, and they were losing ground.Kowalski reached to the door and fought the handle. “Locked.” He punched the metal surface in frustration.Coming up to his side, Gray noted an electronic key-lock below the handle. The lighter’s flame flickered across a small steel sign stenciled in Art Deco letters:NATIONAL MUSEUM OF AMERICAN HISTORYThe door was a subterranean entrance to another of the Smithsonian Institution’s museums. Closest to the door, Elizabeth swiped her museum security card, but the lock remained dark.
