The avenging confederates of a captured robber burst into the station house, taking interrogators Katy and Gianelli hostage.
Katy goes after the money-laundering ring responsible for her slain partner's (Robyn Douglass) soiled reputation; guest Dennis Farina.
The investigation of armed robberies pits Katy against a motorcycle gang and its psychotic leader, a former Green Beret.
McNichols and Mahoney race to break up a drug ring formed by a crime family and an ambitious European assassin.
McNichols races to track down Katy, suffering violent reactions after a crazed gunman injects her with a hallucinogen.
McNichols and Katy try to thwart terrorists planning to blow up a downtown lottery office; guest Vincent Baggetta.
A major crime syndicate's imprisoned matriarch puts out a contract on Katy and the lawyer (Chip Lucia) responsible for her conviction.
A model (Jodi Wright) helps Katy trap "the hunter" (Niles McMaster), a murderer who uses bizarre weapons.
A friend's death leads Katy to a mysterious assassin (David Chow) murdering Vietnamese refugees seeking political asylum in Chicago.
Katy relentlessly searches for a serial murderer who is mutilating his victims; guest Johnny Depp.
Attempting to quell a sudden outbreak of gang violence, Katy notices two young lovers caught in the crossfire.
Chicago detective Katy Mahoney gets little help from the housing-project victims of a brutal ex-convict (Frank Rice).