Deputy U.S. Marshal Casey Sloane has worked at the St. Louis marshals office for two years and is given a routine assignment to help transport a reporter to D.C. to testify before a grand jury. Valerie, the reporter, was writing a story about an up-and-coming environmentalist who suddenly disappeared and, she later discovered, whose backers purportedly have ties to a terrorist.

When the seemingly ordinary assignment suddenly takes a shocking turn, Casey is forced to put aside her own feelings about the unexpected reappearance of a man from her past as she and two other marshals take...