In Plain Sight is a crime drama starring McCormack as Mary Shannon, a U.S. Marshal working in the highly secretive branch of the witness protection program (WITSEC) who relocates Federal Witnesses - many of them who are career criminals, and many who are innocents that had the misfortune of witnessing a crime. They all have one thing in common – someone wants them dead. Mary's job is to see that doesn't happen, while at the same time attempting to manage her own dysfunctional family.