Raymond Burr essays a dual role in this offbeat episode, appearing as both Perry Mason and Mason's evil lookalike, a scurrilous merchant seaman named Grimes. It seems that someone has hired Grimes to pose as Mason in order to discredit the lawyer's testimony in a hearing over a million-dollar patent dispute. Subsequently, the winner of the dispute, Otis Swanson (Oliver McGowan), is murdered, and innocent Barbara Kramer (Indus Arthur) is arrested for the crime. To save Barbara from the gas chamber, Perry must literally chase himself by tracking down the elusive--and dangerously short-tempered--Mr. Grimes. ~ Hal Erickson, Rovi