Danny and Baez set out to investigate the murder of Kathleen D'Amato, a young Italian-American woman found dead in a cemetery. After speaking with father to learn she was a pious Catholic girl, they are surprised when Kathleen's classmate informs them she was studying Arabic and was involved with a Muslim boy. When he and his antagonistic brother are ruled out for the murder, Danny and Baez turn to Kathleen's bigoted ex-boyfriend Joe as a possible suspect. Joe reveals that Kathleen had converted to Islam, and his verified alibi leaves them with the belief that her devout Catholic father could have committed the crime. Danny and Baez coerce Kathleen's father to confess that he inadvertently killed her when she asked for his acceptance of her new faith. Meanwhile, Frank and Jamie hunt down a former NYPD officer out for revenge against his former precinct.
