A complex murder-suicide case has the department reeling. Meanwhile, when Rusty receives a mysterious and threatening letter Emma demands that he be relocated.

The LAPD flies a material witness into Los Angeles to testify, but in a horrible turn of events their witness winds up as the key suspect in an entirely new murder. Personal and professional stress takes a toll on Flynn. And the squad takes bets when Rusty brings a girl from class to hang out with him at the department.