Russell's replacement investigates a possible abduction with Lydia, while Nate & Sammy check out a shooting that's part of an undercover operation.
While investigating a triple homicide, Lydia and Rene realize they have very different styles of detective work; And Ben confronts John about his reliance on pain pills.
Ben winds up in a patrol unit alone for the first time. Among the cases he has to handle on his own are a missing girl and a suspected stalking case
Lydia and her new partner, Ray Suarez, arrive in Compton, where a young USC student was murdered
After gangsters open fire in a crowded club, tensions rise between Sal and Gil on the gang task force. And Sammy confronts his wife about crossing the line too often.
The Southland officers are sent out to capture a rapist impersonating a cop. While Lydia's reunited with her former partner, Russell, Sal's secret affair is revealed to his wife.