Athena's boss stops by her home to inform her that the gun responsible for the death of her fiance, Emmett Washington, was found.
Flashbacks to 1989 show a young Athena meeting Emmett on campus while she was at college. He recruited her to join the LAPD and after some time she decided to quit law school and join the force.
In the present day, Athena gathers information about the person who was found with the gun from Emmett's old partner's computer. He later confronts her and gives her a file of information about the case.
In the past, Athena is paired with Officer McCluskey, who teaches her about the job, and she and Emmett grow closer and he eventually proposes. While she's trying on wedding dresses, she asks Emmett to get coffee creamer from the store, and he ends up being killed during a robbery there gone wrong.
Athena investigates the case against the wishes of Bobby and others and links the gun to an old motel. With Maddie's help and 911 records, she gets information about a man who overdosed the night of Emmett's murder and tracks him down.
The man, Dennis Jenkins, admits to being high and murdering Emmett. Athena takes him into custody and then informs Emmett's mother that an arrest has been made thirty years later.