When Jim and Carlos investigate the death of a millionaire who bequeathed all his wealth to an organization of UFO enthusiasts, the organization's leader accuses the FDLE of covering up the true cause of death: an alien abduction. Meanwhile, Jim and Callie's relationship heats up, but Callie's job search to keep her in Palm Glade falters.

A beautiful synchronized swimmer in an elaborate mermaid costume washes ashore dead, and the clues lead Jim to a bittersweet love triangle and a hip hop mogul trying to turn a mermaid show into multimillion-dollar phenomenon. On the home front, Callie hits a wall in her job search, and Jim realizes the best opportunity for her is the one in Atlanta she passed up to be with him.

While Jim helps Callie settle into her new apartment in Atlanta, Carlos performs a guest autopsy for Daniel's forensics class at Tampa Tech. He discovers that the cadaver he is dissecting is actually a murder victim who turns out to be a student that was killed while participating in an on-campus pharmaceutical study. Also, the Palm Glade substation gets a new addition when FDLE Bureau Chief Jennifer Starke comes down to visit Manus, while Callie gets off to a rocky start with her new boss Dr. Miranda Buckley.

The dead body of a naked woman leads Jim and Carlos to investigate a close­ knit nudist colony fighting against expansion by a luxury condo development. Jennifer begins interviewing the substation employees and finds its high case closure rate seems directly related to Jim, in whom she takes an interest that may be more than just professional.

When Jim finds the ex-Navy Seal owner of his favorite food truck dead in the truck's kitchen, he ends up embroiled in a heated political battle between the new wave of gourmet food trucks and the established boardwalk restaurants. Jennifer takes an active and prying interest in Jim's cases, while Callie's attempt to confront Miranda about her hostility backfires.

The murder of a woman who contacted the Innocence Project to exonerate a death row inmate now forces Jim to team up with the detective who investigated the original case: Jim's former partner when the Florida State Attorney General's office calls her to testify against the IRS agent who handled her audit and tried to extort her for sex a few years back. Reluctant to take time off to help the State Attorney, Callie is surprised when Miranda is not only supportive of her request, but also learns that Miranda has been the victim of sexual harassment herself, and the two women bond through their shared experience.

Longworth and Jennifer investigate a murder that puts them at odds with the Sovereign Citizens, a bizarre anti-government group that believes they are above the law. Manus and Carlos soon find themselves victims of the Sovereigns' paper terrorism attacks when they are suspended from duty. Callie desperately searches for her old cell phone where she recorded Elkins blackmailing her into sleeping with him for overlooking her tax issues.

When the co-owner of a luxury medical spa turns up dead, Jim and Jennifer investigate the spa's members and discover the high costs the wealthy pay in order to stay looking young and beautiful. Callie gets anxious while both studying for her boards and preparing for her testimony against Elkins. Her house in Palm Glades is falling apart, but her life in Atlanta is picking up.

The body of an $80-million Florida state lottery winner is found murdered on a remote island in Islandia, and Jim and Jennifer must unravel a personal vendetta spanning over a decade between the victim and the island's only resident. Miranda pulls Callie away from her studies to have some fun at a medical sales mixer, but Jim starts to find Callie harder and harder to reach in Atlanta.