Frequency

Detective Raimy Sullivan begins receiving messages from her late father through an old ham radio, and she attempts to alter the course of events to prevent his death.

Raimy contacts Frank via ham radio to warn him that her mother will be killed unless he can find a way to prevent it, while also revealing shocking news about Stan Moreno. In 2016, Raimy pursues a new lead in the Nightingale investigation, while in 1996, Frank and Satch follow the same lead in parallel.

Raimy discovers new evidence in the Thomas Goff case and shares it with Frank via ham radio, leading him to act independently despite Satch's warnings. At the same time, Gordo persuades Raimy to join him for a drink, where she meets Daniel, who remains wary of her. Both Raimy and Frank face challenges adjusting to life without and with Julie, respectively.

As Julie's abduction date nears, Raimy and Frank seek information from a girl whose mother was kidnapped by the Nightingale. Raimy meets Kyle, a man who recalls a past encounter with her, though she initially does not recognize him.

Raimy works with Frank to investigate a current murder by examining historical clues, which triggers two conflicting memories of her first day as an NYPD officer. As Frank helps Raimy uncover more about Stan, tensions arise with Satch, while Frank also grapples with jealousy in his efforts to respect Julie's independence.

In this episode, the main characters face unexpected challenges that test their relationships and force them to make difficult decisions. As tensions rise, secrets begin to surface, altering the dynamics within the group. The episode ends with a major development that sets up future conflicts.

Raimy and Satch make progress in their investigation as a cold case connection points them to a significant lead: a room where the Nightingale's first victim was held.

Raimy and Satch uncover a surprising link to the Nightingale's first murder, prompting Raimy to confide in Frank, who begins investigating further. At the same time, Frank and Julie engage in a candid discussion, and Raimy receives an unexpected visit.

Raimy and Frank uncover a surprising truth about the mysterious Nightingale, leading to new questions about its origins and intentions.

Frank and Raimy begin working together to develop a strategy for Frank to eliminate the Nightingale.

Raimy and Frank become deeply involved in a developing situation. At the same time, Frank uncovers the reason behind a personal betrayal.

Raimy and Frank uncover a significant clue in their ongoing investigation to locate the elusive Nightingale.

In the season finale, Raimy uncovers a surprising truth that prompts her to contact Frank to discuss her worries.