Southland - Season 4

In the fourth season premiere, Officer Cooper gets a new partner -- Jessica Tang (Lucy Liu); and Lydia has a new partner as well -- Ruben Robinson (Dorian Missick).

Tang and Cooper are attacked on the street, while Lydia and Ruben question the unassuming grandmother (MARLA GIBBS) of a murder suspect. The force gets a new captain.

Bearing a grudge, Sammy leaves a gang territory unattended, only to have a violent gang war erupt throughout the city. Ben's recent mistake continues to haunt him everywhere.

Jessica tries to help a homeless vet get an ID so he can be admitted to the homeless shelter. Sammy's determined to save a dog after he accidentally shot it in the leg.

Cooper tries to save a suicidal teen in a situation that hits close to home, while Jessica gets a visit from someone in her past. Sammy enlists an informant - with tragic results.

Sammy tries to make amends after the murder of a young man who agreed to testify in one of his cases. John and Jessica find themselves babysitting a documentary film crew.

Jessica's day goes from bad to worse in a shootout. Sammy holds a grudge against Ben for not backing him up during an arrest. And Lydia reaches a decision about her life.

While Tang gets an update about the boy she shot, John wants her to come clean about what really happened. Ben tries to intervene in the life of a prostitute, but makes things worse.

Ben heads down a slippery slope as he attempt to help the daughter of a prostitute, while Tang faces more questions about her shooting of an innocent bystander - which could affect her future.

In the season finale, Tang prepares to move on to a new precinct, but first she wants to tie up some loose ends on the beat. Lydia is pressured to make a decision about her future.