In the fourth season premiere, Griffith Park is a blazing inferno, threatening sections of Los Angeles, Glendale, Burbank and San Mateo. With four people dead and firefighters desperately trying to keep the flames at bay, the Priority Homicide Division is called in to begin an investigation. Things turn ugly when an old nemesis of Brenda's -- pyromaniac Bill Croelick (guest star JASON O'MARA Life on Mars, "Grey's Anatomy," "Men in Trees") -- enters the scene. To make matters worse, a reporter has been attached to the squad as part of a PR campaign for the LAPD. On the home front, Fritz and Brenda have moved into a duplex, but the owner doesn't allow pets. This doesn't stop Brenda, however, from doing everything she can to keep Kitty under wraps, even if it means fighting with Fritz over the situation.

A recently paroled murderer is found dead in an alley near a halfway house, the victim of a hit and run. Brenda must tread carefully, because the crime for which the victim was convicted was a major press event in Los Angeles. Flynn was the primary on the original case, and the wounds he feels from it are still painful, even eight years later. At home, Fritz spends the day lying on the floor after throwing his back out.

After reporting to the police that she had been raped by one of her classmates, a high-school girl apparently hangs herself in her bedroom. But Brenda is not so sure it's a suicide, especially given that the boy who allegedly raped her is the son of Mark Yates (guest star DANIEL BALDWIN - "Homicide: Life on the Street"), a Los Angeles County Sheriff's Dept. commander. Despite some major head-butting between Brenda's squad and the overheated and overprotective Yates, Brenda's intense investigation eventually uncovers a ruthless sexual game being played at a local private school.

A man wearing a surveillance wire in downtown Los Angeles is shot to death at point-blank range and the first person on the scene is none other than Ricardo Ramos (guest star STEPHEN MARTINES - "General Hospital"), who covers Priority Homicide for the Los Angeles Times. The victim's connections to a drug investigation intersect with Fritz's FBI work, and the ongoing duel between Brenda and her fiancé for control of the case leads to confrontation.

Posing as hit men, Provenza and Flynn successfully bring an attempted murder sting operation to a close only to find all their evidence, along with Provenza's car, has been stolen while they stopped for lunch. Brenda, forced to free her suspect, must face a furious Pope, who insists that Priority Homicide must get the car, the evidence and the suspect back in 48 hours. JENNIFER COOLIDGE ("Best in Show," "Legally Blonde," "Joey," "Nip/Tuck") guest stars.

When a rebellious, adopted 12-year-old boy disappears, Brenda must decide whether he should be treated as a runaway or as a critical missing person. The further into the case she goes, the more toxic the child seems to be, and Brenda begins to question if the missing boy is a victim -- or a potential killer.

After Detective Sanchez's brother is shot, the entire squad will not rest until they find the culprit. The investigation is jeopardized by an overzealous detective and a leak within the department. KEVIN BACON directs the episode.

After a hairstylist for a television show is murdered, Brenda and the squad must wade through a history of domestic violence and secret addresses to find the murderer. Brenda also has to deal with her parents, Willie Ray and Clay (recurring guest stars FRANCES STERNHAGEN and BARRY CORBIN), who have decided to pay a surprise visit in the RV on their way to Alaska. Brenda's father drops blatant hints wondering when they can expect Brenda and Fritz to finally tie the knot.

The bodies of two Tijuana police officers are found in the back of a stolen pickup truck, and all the evidence points toward an FBI informant as the prime suspect. But with corruption among police officers in Tijuana extremely common, it's difficult for Brenda's squad to know whom to trust. Complicating matters, a newspaper story by Ricardo Ramos (recurring guest star STEPHEN MARTINES) paints an extremely unflattering picture of Priority Homicide, a public relations nightmare that's going to require some fancy footwork by Pope, Taylor and Brenda to set right.