Katherine Adams stepped from the train at Oakwood, glanced expectantly up and down the station platform, hesitated a moment, and then, picking out a conspicuous spot under a glaring arc light, deposited her suitcase on the ground with a thump, mounted guard beside it and patiently waited for Nyoda to find her in the surging crowd. It was two days before Christmas, and travel was heavy. It seemed as though the entire population of Oakland was either...