Former literature professor Harriet “Harry” Wild is trying to adjust to retirement when she’s injured in a mugging. While recovering at the home of her son, senior detective Charlie, Harry looks at his files and realizes his latest investigation bears similarities to an obscure Elizabethan play. After Charlie dismisses her insights, she decides to find the killer—with aid from a surprising source.

Due to their new notoriety, Harry and Fergus are approached by a woman desperate to find out how her husband died. Although reluctant to get involved, Harry’s interest is soon piqued. When she and Fergus uncover a deadly gambling operation, Harry turns over the evidence to Charlie, vowing to stay out of it. Unfortunately, the killers have other ideas.

When a body is pulled out of the river near Harry’s local pub, something about the dead man feels familiar to Harry. When she remembers how she knows him, she realizes she’s stumbled onto the ultimate misdirect. Harry and Fergus go undercover, with the assistance of Harry’s teenage granddaughter, Lola, to find the truth. Along the way, Harry starts to grow closer to Ray, Charlie’s boss and mentor.

Harry and Fergus agree to help a local loan shark known as Happy find out who murdered his employee; in return, Happy will cancel the sizeable debt owed by Fergus’s father. Harry notices links between the killing and Dostoevsky’s “Crime and Punishment,” which brings her to the attention of fledgling serial killer Billy Lund.

A stuffy dinner party in the home of Harry’s former colleague goes awry when a vomiting bug hits all the guests but Harry. After the cause of the sickness is traced to a dead body in the home’s well, Charlie’s sergeant, Vicky Boyle, leads the investigation. Too eager to prove herself, Vicky makes some rash choices and zeroes in on Harry as the culprit, leaving Fergus to prove her innocence.

A violent storm traps Harry, Fergus, and Lola in the local pub. Cut off from the outside world by flooded roads and downed phone lines, the trio are put in even more peril when they discover a kidnap victim in a car. After freeing the man, they realize the kidnapper must be one of the handful of strangers trapped in the pub with them.