In 1974, a revolutionary group calling itself the Dread Scott Brigade held up the old Shawmut Bank in Boston. Money was stolen. And a woman named Emily Gordon, a visitor in town cashing travelers checks, was shot and killed. No one saw who shot her. Despite security camera photos and a letter from the group claiming responsibility, the perpetrators have remained at large for nearly three decades. Now Spenser tries to solve the murder as a favor to an old friend.