Murder in the First

SFPD Detectives Terry English and Hildy Mulligan are quickly thrust into the middle of a brutal onslaught as two students open fire on a school bus in the middle of the city. San Francisco's finest must work quickly in order to put an end to one of the deadliest shootings in recent history, as one gunman is captured, and the other escapes.

Tensions mount as the manhunt for the missing shooter proves to be more difficult than expected. Terry is promoted to acting Lieutenant, which he soon discovers comes with responsibilities more taxing than he anticipated.

As the city reels from the school bus tragedy, newly appointed D.A. Mario Siletti promises justice for the victims. Terry receives new evidence about the recent death of a cop, leading him to believe it may have been of a more insidious design. Meanwhile, the body of a young Chinese gang member found in an urban grow house, leads Hildy into the dangerous world of drugs and gang politics.

Raffi fears Hildy's continued investigation of the grow house murder will blowback on a case of her own.

The pressure ratchets up on Terry and Hildy to discover who's behind the cop-killings. Jamie comes out swinging, making an unexpected move in her defense of Dustin. Navarro reunites with his brother, who has been recently released from prison. Meanwhile, an anonymous tip gives Raffi a potential connect for her case against Suger.

Terry and Hildy find themselves investigating people within their own department. Jamie digs into Dustin's past in an effort to better understand his actions. Meanwhile, Suger searches for answers as someone close to him disappears, then makes a shocking discovery.

The truth about Navarro leads Terry and Hildy to Mexico, as an angry Suger prepares for war. Jamie's casework takes her to Pleasantville, and a particularly painful event from Dustin's childhood. Raffi's investigation into Suger takes an unexpected turn.

Junior reveals new details which may finally give Hildy and Terry the upper hand in their investigation, while the Trial of Dustin Maker begins with opening statements. Meanwhile, an unlikely source provides Suger with startling new information regarding his sister.

Terry and Hildy's investigation is dealt a lethal setback, forcing them to close their case. Raffi's loyalty comes into question, while a cautious Suger contemplates the future of Potrero. The stress of the trial takes a dramatic toll on Jamie's personal life.

While Jamie deals with the fallout from her tirade, witnesses take the stand in the case against Dustin. When threats are made against her family, Hildy vows to take down The Union once-and-for-all.

Terry and Hildy take a high-ranking officer into custody, while Suger faces a new and unexpected threat to Potrero. Meanwhile, Molk uncovers unsettling information about a potential prostitution ring.

In the season finale, Terry and Hildy are gloves-off as they race to close in on a murder suspect, while Fatty B lobbies to take Potrero in a new direction. The Trial of Dustin Maker reaches a climactic verdict.