After the sudden death of his superior, Bill Hollister finds himself navigating uncharted waters when he takes his place as Los Angeles County Sheriff.
As Bill continues to have a hard time adjusting to the dull roles of his new position, he sets out to track a criminal who got into trouble after getting released from prison. Tragedy strikes when Luna is shot.
Following Luna's shooting, Bill and the entire department set out to find the one responsible. As Bill follows a lead, he tracks down the shooter who turns out to be a mentally ill man.
When a former informant of his is arrested during a riad, Bill tries to protect her, while she gives away her fellow smuggler. Undersheriff Jerry London uses Minnick to spy on Bill.
Joseph enlists Bill's help to uncover the truth, when his childhood friend is wrongfully accused by the LAPD. Paula finds herself in a dilemma when she's asked to fire staff in order to meet the hospital's budget requirements.
Paula is taken hostage at the county jail, after which an inmate and his girlfriend force her to perform a surgery on him. Bill sets out to do everything in his power to save her and stop the dangerous couple.
As a large fire breaks out in Santa Clarita, Bill accompanies Cade on a mission to locate a missing girl, where they track down the abductor. Maggie loses it after reporters stake her family house.
Cade investigates the murder case of a homeless veteran, while Bill has to make a decision about whether or not he declares his candidacy for the sheriff position. Paula and Maggie are struggling to deal with the pressures of Bill's new position.
Bill investigates a series of burglaries that turn out to be executed by rich kids who are seeking fame. Paula's mother comes for a visit in order to help with Maggie's quinceañera. Bishop has an unpleasant confrontation with Genevieve.
When Minnick's friend gets mixed up with a gang, she and Bill set out to protect her and catch the cartel enforcer. Minnick ends her relationship with London, as she no longer wants to betray Bill's trust.
After Minnick and Joseph arrest a man with a fake ID, he turns out to be a cocaine trafficker who is about to close a major deal. As DA Riley digs into Bill's past, he considers not running for the position to spare his family the trouble.
As Minnick and Joseph investigate the murder of a rich man, Cade struggles to keep the grandmother of his foster children from getting custody of them. DA Riley threatens Bill and Joseph, while London is still trying to win the position at any cost.
When the Mayor is abducted and informants are being targeted, Bill sets out to find the mole in the department and save the Mayor, while making it just in time to Maggie's quinceañera.