Thoreau in Phantom Bog

Thoreau returns to Plumford, Massachusetts in search of a fellow conductor on the Underground Railroad who has gone missing. With the help of his good friend, Dr. Adam Walker, Thoreau finds the conductor--shot to death on a back road. After another conductor is murdered in a neighboring town, a letter is found from someone claiming to have been hired to assassinate anyone harboring fugitive slaves. With all of them now potential targets, Thoreau and Walker urgently need to find the killer.