U.S. Marshall Mary Shannon must hunt down witnesses for federal cases in the witness protection program while also raising a rather dysfunctional family and her own personal life.

Mary Shannon: [intro] Since 1970, the Federal Witness Protection Program has relocated thousands of witnesses, some criminal, some not, to neighborhoods all across the country. Every one of those individuals shares a unique attribute, distinguishing them from the rest of the general population. And that is, somebody wants them dead.
Marshall Mann: [Answers phone] House of pie.