Grace Hanadarko is an Oklahoma City police detective with an alcohol problem and a self-destructive lifestyle. After she hits a man with her car while driving drunk, she asks God for help and an angel named Earl appears. Earl wants to help her find the right path of life again, but it is going to be a hard piece of work for both of them.

Grace and her team investigate the murder of a manager of a sleazy local motel. The investigation eventually leads to a maid, who claims the victim was trying to rape her. Complications arise when a local priest offers her the right of sanctuary. Meanwhile, Grace begins to accept Earl's presence in her life.

Grace and the guys investigate the murder of a “crispy critter” in the Oklahoma countryside and Bobby soon discovers the deceased was one of his mentees. Grace enlists the help of her Native American grandfather, “Geepaw,” to help with the case, but is shocked when she sees how quickly his health is deteriorating. Grace and her sister, Paige, fight over many things, including Geepaw’s future in a nursing home. Earl tries to make Grace realize the importance of family… and Grace and Butch rekindle their passion.

During the raid on a killer's house, Grace gets shot and almost dies, while another policeman isn't as lucky as her and gets shot to death.

Meanwhile, Leon Cooley has to deal with his ex-wife marrying another man, who might adopt his son.

A photo of Grace's sister, Paige, is found in a burning car.

Grace struggles with what she should do about father Murphy. Off duty from calling in sick she winds up capturing number six on the FBI's most wanted list while meeting Gretta. After Grace brings in father Murphy he winds up dead and she's suspected.

A teenage girl dies at a school friend's party that Grace's niece was at; Grace has a new partner; Johnny tries to learn more about Earl.

The team blows Bobby's cover when they investigate a murder; Grace has suspicions about Abby; Rhetta and Johnny meet with Leon.

Grace takes on an investigation when a jogger with a intricate love life is found dead. Meanwhile, Clay's father and a new bartender from a local joint begin dating, and Grace worried that this will have a negative impact on Clay. Leon gets a visit from a former high school classmate.

Doug and Maggie's romance has flourished so much that they set their wedding date, but the date may be put on hold when Maggie is attacked by an unknown predator. Meanwhile, Johnny and Rhetta try passionately to save Leon from his upcoming execution by starting a petition. And young Clay continues bonding with Leon's son.

As the squad investigates a fatal shooting by an elderly woman, Leon Cooley’s execution date arrives. Grace, who has discovered that Leon once helped her sister and was invited to a family birthday party, struggles with whether or not to lend a hand towards stopping the execution. Grace also finds a connection with a young woman, who may also be getting visits from Earl. And Ham’s divorce is finalized, which he hopes will make things between him and Grace more permanent.