They call them Travelers. They move from city to city, panhandling, committing no crimes-they just like to stay on the move. And now somebody is killing them. Lucas Davenport's adopted daughter, Letty, is home from college when she gets a phone call from a woman Traveler she'd befriended in San Francisco. The woman thinks somebody's killing her friends, she's afraid she knows who it is, and now her male companion has gone missing. She's hiding out...