FX: The Series is loosely based on the two F/X feature films, which starred Bryan Brown and Brian Dennehy. It is the story of special effects wizard, Rollie Tyler, played by Australian actor Cameron Daddo, and his friend and coworker, Angie Ramirez (Christina Cox). Together, they use their genius in special effects to create movie magic and to help the police solve difficult crimes. During the first season, veteran actor Kevin Dobson played the role of Leo McCarthy, a detective in the NYPD and Rollie's long-time friend. Together, they would use special effects and canny police work to bring down criminals who might otherwise have escaped justice. Other important recurring characters were McCarthy's partner Francis Gatti (Jason Blicker), actress Lucinda Scott (Carrie-Anne Moss) and Captain Marvin VanDuran (Richard Waugh).
At the opening of the second season, Leo was tragically killed in a bomb explosion. The new character of Mira Sanchez (Jacqueline Torres), a detective in the Internal Affairs division of the NYPD, was introduced. Mira transferred out of Internal Affairs, but continued as a detective in the department. In time, she became a friend to Rollie and Angie, who continued to help the police on cases.