Clutching a dagger, a woman enters a room through velvet portieres and murders Nathan Standish, the scion of a distinguished family. Nathan's sister Sylvia hides the knife, and when the butler Bobbins - whose hatred of Nathan was well-known - is arrested, Sylvia remains silent. To please her father, Sylvia marries the prosecuting attorney Paul Wagner. When she secretly tries to help free Bobbins, detective Bull Ziegler, who believes that Bobbins is innocent, suspects Sylvia. After Sylvia's hysterical speech during sleep leads Wagner to suspect her, she becomes insane. Wagner and her father take her to a mountain retreat where she recovers her sanity without regaining her memory. Just as Ziegler is about to have Sylvia arrested, a telegram arrives informing them that Sylvia's cousin committed suicide and left a note stating that she killed Nathan in revenge for being betrayed by him. Sylvia, who tried to protect the family name, recovers her memory when she learns of the suicide.
Original title announced to press was "The Unafaid."